UNIT#06 CHEMICAL EQUILIBRIUM Flashcards
At equilibrium, the concentration of reactants and products are:
Constant
A statement which describes a reversible reaction:
Both forward and reverse reactions occur simultaneously under the same conditions
One mole of HI was sealed in a tube at 440°C till equilibrium is reached, HI was found to be 50% dissociated, and Kc for the reaction is:
0.25
For what value of Kc almost forward reaction is complete:
Kc = 10^30
1 mole of ethyl alcohol was treated with one mole of acetic acid at 25°C. 2/3 rd acid changes into ester at equilibrium. The equilibrium constant of the reaction will be:
4
At equilibrium concentration of SO2 is 2M, O2 is 2M and SO3 is 4M.
2SO2+O2→2SO3
What will be the Kc value of a given reaction?
2
In a reaction CO + 2H2 ➡CH3OH 🔺H=-92kj/mol.
Concentrations of hydrogen, carbon monoxide and methanol become constant at equilibrium, what will happen
The equilibrium state remains undisturbed
If the Kc value is very small then the equilibrium position will shift:
Towards left
The equilibrium expression for a reaction is Kc= X2/V(a-X), which is true for the reaction.
Decrease of pressure favoured forward reaction
For the reaction H2 + I2 ➡2HI. The equilibrium constant changes with:
Temperature
The correct relationship between Kc and Kp can be written as:
Kp=Kc(RT)🔺n
For the given reaction H2+I2➡2HI. the equilibrium concentration of H2, I2 and HI are 8,3 and 24 mole/dm^3 respectively. Kc of the reaction is:
24
For the following reaction in the gaseous phase:
CO+1/2O2 ➡CO2, Kc/Kp is:
(RT)1/2
In the reaction A2 + 4B2➡2AB such that 🔺H is negative, the formation of AB will be favoured at:
➡Low Temperature
➡High Pressure
N2 + 3H2➡2NH3
The forward reaction is favoured by:
Decreasing Temperature
In a given system, water and ice are in equilibrium, i the pressure is applied to the system then:
More ice is melted
If the temperature is increased for the following reaction, then it will go in:
N2 + 3H2➡2NH3 🔺H=-ive
Reverse reaction
In the Haber process, the equilibrium mixture contains ___ NH3 by volume
35%
The catalyst used in Haber’s process for the manufacture of NH3 is:
Fe(MgO, Al2O, SiO2)
The basic buffer solution is:
➡NH4OH
➡NH4Cl
Buffer action can be explained by all except:
Solubility Product
A basic buffer solution can be prepared by mixing:
Weak base and its salt with strong acid
The pH of the ideal buffer is:
7
A certain buffer solution contains an equal concentration of X and HX. Ka for HX is 10^-8. The pH of the buffer is:
8
Which Henderson equation is correct:
➡pH = pKₐ - log([acid]/[salt]
➡pH = pKₐ + log([salt]/[acid]
➡pKa =pH - log([salt]/[acid]
For acidic buffer, pH < pKa if:
[salt] < [acid]
When HCl gas is passed through a saturated solution of rock salt, the solubility of NaCl
Decreases
An excess of silver nitrate is added to the aqueous barium chloride and the precipitate is removed by filtration. What are the main ions in the filtrate
Ag+ and NO3- and Ba+2 only
Ionization of KClO3 is suppressed by:
Adding KCl
If the ionic product is equal to Ksp, then the solution is:
Saturated
The solubility product is only applicable for those substances whose molar concentration is:
Equal to or less than 0.01
In a saturated solution of AgCl, the molar concentration of Ag+ and Cl=- is 1.0 x 10^-5 M each. What is the value of Ksp
1.0 x 10^-10
The molar solubility of sparingly soluble salt AB3 is “S” mol/dm^3, the corresponding solubility product Ksp is given in terms of Ksp by the reaction
S= (Ksp/27)1/4
Units of Kc for the following reaction is: H2 + I2 ➡2HI
No unit
If in AgCl solution, some salt of NaCl is added, AgCl will be precipitated due to:
Electrolyte
The formation of NH3 is a reversible and exothermic process, what will happen on cooling?
More products (NH3) will be formed
A buffer solution is that which resists/minimizes the change in:
pKb
The chemical substances, when dissolved in water, give “H” is called:
Acid
The ‘pH’ of our blood is:
7.9
The value of equilibrium constant Kc for the reaction 2HF➡H2 + F2 is 10^-13 at 2000°C. Calculate the value of Kp for this reaction
10^-13
What will be the pH of a solution of NaOH with a concentration of 10^-3M
11
During the manufacture of nitric acid, nitric oxide is oxidized to nitrogen dioxide. This reaction is given to:
2NO + O2 ➡ 2NO2 🔺H=-114kJ/mol
According to Le Chatlier’s principle:
The reaction must be carried out at a low temperature
Which one of the following is the correct representation for Ksp?
AgCl ➡ Ag+ + Cl-
Ksp [Ag+1][Cl-1]
Human blood maintains its pH between:
7.35-7.55
The value of Ksp for the PbSO4 system at 25°C is equal to:
1.6 x 10^-8 mol2dm-6
For which of the following equilibrium reaction, Kc has no units;
CO + H2O ➡CO2 + H2
Ca(OH)2 is sparingly soluble having a solubility product value of 6.5 x 10^-6. What will be its solubility
1.17 x 10^-2
The product of the concentrations of each ion in a saturated solution of a sparingly soluble salt at 298K raised to the power of their relative concentrations is:
Ksp
Which of the following factors affect a reversible chemical reaction in accordance with Le-Chatlier’s principle?
➡Pressure
➡Temperature
➡Concentration
Which one of the following factors does not affect the equilibrium positions?
Catalyst
The Kc Unit for the reaction N2 + 3H2 ➡2NH3 are:
mole-2 dm+6
Which one of the following bases has the highest Kb value?
NaOH
What is the pH of 0.1M of HCl?
1
The pKa value of CH3COOH is 4.74, and the pH of an equimolar solution of acetic acid and sodium acetate is:
4.74
Does precipitation occur when the product of ionic concentration is?
Greater than Ksp
Kp = KC (RT) in the equation if 🔺n<0 then:
Kp < Kc
PKa values of some acids are given below choose the weaker acid.
H2SO4
(-3)
Consider the reversible reaction
N2 + 2NH3 ➡2NH3 + Heat
The yield of NH3 will be maximum at:
➡Low temperature
➡High pressure
Ice and water are in equilibrium with each other. By increasing the pressure the equilibrium will shift in:
Forward
For an equilibrium reaction;
2SO2 + O2 ➡ 2SO3
The forward reaction is exothermic, an increase in temperature shifts the equilibrium position towards the left because:
The concentrations of SO2 and O2 increase and the concentration of SO3 decreases as the temperature increases
Which of the following reaction has greater Kp than Kc (Kp > Kc)?
2NOCl ➡ 2NO + Cl2
The equation N2 + 3H2 ➡ 2NH3 represents:
Haber’s process
For a gaseous phase reaction, when a number of moles of reactants and products are equal:
The value of Kp and Kc is the same
Purification of table salt (NaCl) by passing HCl gas through its saturated aqueous solution is an example of;
Common ion effect
The conversion of nitrogen to ammonia or nitrogenous compounds is called:
Nitrogen Fixation
The reversible reaction is:
Non-Spontaneous
H2 + I2 ➡2HI relation between Kp and Kc for this reaction is:
Kp = Kc
Production of ammonia by the Haber process is made economical by using:
Le Chatlier’s principle
With different numbers of moles of reactants and products the volume of the system:
Changes
Kc and Kp have the same value when reactants and products have the same number o:
Moles
Reversible reactions are:
Non-spontaneous
Production of ammonia by Haber process is made commercial by using
Le Chatlier’s principle
According to Le Chatlier’s principle, exothermic reactions are favoured by:
Decrease in Temperature
Kp = Kc (RT)🔺, T stands for:
Absolute Temperature
Manufacturing of Ammonia by Haber’s process is an:
Exothermic Reaction
The equilibrium constant for ideal gases in terms of partial pressure is denoted by:
Kp
Classification of solids is based upon the arrangement of:
➡Molecules
➡Atoms
➡Ions
A very small value of Kc depicts:
Little Forward Reaction
The equilibrium constant is always written as a ratio o:
Products over reactants
At equilibrium the concentration of reactants and products are
Constant
Statement, which describes a reversible reaction
Both forward and reverse reaction occur simultaneously at the same time under same conditions
In a given system, water and ice are in equilibrium, if the pressure is applied to the system then
more ice is melted
If Kc value is small then equilibrium position will shift
towards left
Value of Kc for H2O at 25°C is
1×10-¹⁴ mol/dm3
One mole of HI was sealed in a tube heated at 440°C till equilibrium is reached, HI was found to be 50% dissociated, Kc for the reaction is
1
For what value of Kc, almost forward reaction is complete
Kc=10³⁰
One mole of ethyl alcohol was treated with one mole of acetic acid at 25°C. 2/3 of acid changes into Easter at equilibrium. The equilibrium constant of the reaction will be
4
In haber process, equilibrium mixture contains _________ NH3 by volume
35%
Catalyst used in haber process for manufacturing of NH3 is
Fe(MgO, Al2O, SiO2)
Which of the following is strongest conjugate base
C2H5O-
The conjugate base of H2PO4-¹ is
HPO4-²
Which of the following is a base according to bronsted lowery concept
I-¹
According to bronsted lowery concept, correct order of relatives strength of bases follows the order
OH- > CH3COO- > Cl-
pKa value of three acid A, B, C are 4.3, 3.3 and 5.5 respectively which represent correct order of strength
B > A > C
Select the pKa values of strongest acid from following
1
Which is correct statement
Ka × Kb = Kw
The Kw of water at 25°C is given by
10-¹⁴
At 90°C, pure water has (H3O+) is 10-⁶ mol/dm3. What is the value of Kw at 90°C
10-¹²
With increase in temperature ionic product of H2O
Increases
The pH of neutral water is 6.8 then the temperature of H2O is
More than 25°C
The value of Kw in an acidic aqueous solution at 298K is
10-¹⁴
Which statement is incorrect
pH and OH- are directly related to each other
Which of the following is not correct
pH= 1/log(H+)
H+ concentration of a solution is 1 mol/ dm3, its pH is
0
What will be the pH of 1 mol/dm3 of H2X, which is only 50% dissociated
0
What is the pH of 0.1M solution of weak acid having ionization constant Ka 10-⁷
4
The pH of 1M MOHsolution which is only 10% dissociated
13
Basic buffer solution is
NH4OH/NH4Cl
Buffer action can be explained by all except:
Common ion effect
Law of mass action
Le chateliers principle
Solubility product
Solubility product
pH of monoprotic acid is 3 at 25°C. The hydrogen ion concentration in the solution would be
0.001
A basic buffer solution can be prepared by mixing
Weak base and its salt with strong acid
pH of ideal buffer is
7
pH of 10-³ mole/dm3 of H2SO4 is
2.7
A certain buffer solution contains equal concentration of X and HX. Ka for HX is 10-⁸. The pH of buffer is
8
For acidic buffer, pH < pKa if
[Salt] < [acid]
If Ionic product is equal to Ksp then the solution is
Saturated
The solubility product is only applicable for those substance whose molar concentration is
Equal to or less than 0.01
In a saturated solution of AgCl, the molar concentration of Ag+ and Cl- is 1×10-⁵M each. What is the value of Ksp
1×10-¹⁰
The solubility product of AgCl is 2×10-¹⁰ mol2/dm6. The maximum concentration of Ag+ ions in the solution is
1.41×10^-5 mol/dm3
The molar solubility of sparingly soluble salt AB3 is S mol/dm3, the corresponding solubility product Ksp is given in term of Ksp by the reaction
S=(Ksp/27)¼
When HCl gas is passed through saturated solution of rock salt, the solubility of NaCl
Decreases
An excess of silver nitrate is added to the aqueous barium chloride and the precipitate is removed by filtration. what are main ions in the filtrate
Ag+ and NO3- and Ba+2 only
Ionization of KClO3 is suppressed by
Adding KCl
For the reaction, 2NH3 → N2 + 3H2
The Units of Kp will be:
(atm)^2
The rate of decrease in concentraion of reactants or that of increase in concentration of products is ___ at the beginning and ___ at the ending.
➡Faster
➡Slower
For the following reaction A + B ⇌ 2C + D. The equilibrium constant unit is;
mol dm^-3
For the reaction A + B ⇌ C + D one starts with 6 moles A and 7 moles B per dm^3. When equilibrium is attained, 4.5 moles o C is formed, what is the value of Kc for the reaction.
5.3
2HI ⇌ H2 + I2
For above reaction if Kc is 0.25, then Kp for this reaction will be:
0.25
Following is the condition of reversible reaction that is not affected by pressure (where Δn = number o moles of product - number of moles reactants)
Δn = 0
Find the Kc o following reaction if equilibrium concentrations of acetic acid, ethanol, ethyl acetate and water are 1.0 M, 1.0M, 2.0M and 2.0M respectively.
4
For the equilibrium 2O3 ⇌ 3O2
The value of Kc= 10^55 at 298 K .It indicates thate:
➡Forward reaction goes virtually to completion
➡O3 is unstable as compared to O2
➡O2 is more stable than O3
If ratio of concentration o products and that of reactants is greater than Kc then reaction will move:
Backward
If the value of Kc is very large for a reaction then the reacton is;
Almost complete
In ___ case increase in temperature and decrease in pressure favours the forward reaction:
PCl5 ⇌ PCl3 + Cl2
If number of moles of reactants are greater than products, then relationship between Kp and Kc is:
Kp < Kc
For the reaction 2HI ⇌ H2 + I2 the equilibrium constant is effected by change in;
Temperature
In which case , decrease of pressure favours forwards reaction
➡At low pressure, equilibirum will shift towards more number of moles
➡At high pressure, equilibirum will shift towards less number of moles
The equilibirum of gaseous reversible reaction that proceeds with decrease in number of moles will shift to right when
Pressure increases
In the following reaction the white ppt i.e. artificial milk (BiOCl) disappears when
BiCl3 + H2O ⇌ BiOCl + 2HCl
More HCl is added
Change in pressure is not favourable to the reactions having reactants and products in
➡Liquid Phase
➡Solid Phase
In an exothermic exothermic reversible reaction ___ tempearture will shift the equilibrium towards the forward direction.
Low
Which one will not affect both equilibrium position and equilibirum constant
Catalyst
When NH4Cl is added in NH4Oh solution then ionization of NH4OH
Decreases
If in AgCl solution ,some salt of NaCl is added, AgCl will be precipattated due to:
Common Ion Effect
Ionization of phenol can be decreased by adding:
Hydrochloric acid
Buffer solution is needed in;
➡Clinical Analysis
➡Soil Sciences
➡Microbiology
A buffer solution has equal volume 0.5M NH4OH and 0.5M NH4Cl.
The pKb of base is 4.74, pH of the solution is:
9.26
Buffer is a solution:
Which resists change in its pH
Select the buffer which is not acidic
NH4OH and NH4NO3
The solubility product of PbSO4 is 4 x 10^6 mol2. dm-6.
The maximum concentraion of Pb2 ions is;
2 x 10-3 mol.dm-3
An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate?
➡Ag+
➡Ba+2
➡NO3-1
For solubility product of solutions ,solubility of salt may be equal to or less then:
0.01M
Calculate the value of Kc or ammonia synthesis when the equilibirum concentraion o nitrogen, hydrogen and ammonia are 2M, 2M and 4M at 400°C
1.0 mol-2 dm6
2A + B ⇌ C + D
In this gaseous mixture, concentraion of all is doubled, then equilibirum constant bbecoems;
Remains the same
The concentrations of the reactants and products at equilibirum aere:
Constant
For which system the equilibirum constant Kc has unit of (concentration)^-1
2NO2 ⇌ N2O4
Appropriate units of Kp for the following reaction is:
PCl5 ⇌ PCl3 + Cl2
Torr
For which of the following reactions Kp>Kc
PCl5 ⇌ PCl3 + Cl2
For the reaction N2 + 3H2 ⇌ 2NH3
Which of the following relationship is correct?
➡Kc = Kp(RT)^2
➡Kp = Kc(RT)^-2
➡Kp = Kc / (RT)2
For which of the folllowing reactions Kc is greater than Kp
2NO + Cl2 ⇌ 2NOCl
Which is the correct relationship?
Kp = Kc (RT)^Δn
When no. of moles of reactants are equal to that of the prodcuts
Kp = Kc
For which of the following reactions Kp > Kc
PCl5 ⇌ PCl3 + Cl2
Decomposition of PCl5 is favoured by
PCl5 ⇌ PCl3 + Cl2
Increase in volume
Kc value indicates that the chemical reaction reaches farthest to the completon
10^15
Kc value for decomposition of HF is 10^-13 at 2000°C. it means that;
Reactants are more stable
Increasing the concentraion of reactants or decreasing the concentraion o the products moves reaction to_____ direction
Forward
The catalyst used for the synthesis of ammonia is:
➡Pieces of iron
➡MgO, Al2O3, SiO2
At very high pressure and low temperature, the rate of formation of NH3 is:
Low
Which statement about following equilibirum correct?
2SO2 + O2 ⇌ 2SO3
The value of Kp falls with the rise in temperature
If a buffer solution of higher pH than seven is to be made we use:
Weak base and its last with strong acid
A basic buffer solution can be preapared by mixing:
Weak base and its salt with strong bas
A buffer solution has equal volume 0.5M NH4OH and 0.5M NH4Cl.
The pKb of base is 4.74. pH of the solution is;
9.26
In buffer solution containing a weak acid and its salt. The ratio of concentraion of salt to acid is increased tenfolds, then pH of solution will:
Increase by one unit
pH of buffer solution containing 0.1M CH3COOH and 1M CH3COONa
(pKa 4.74)
5.74
The solubility product of an ionic compound AB2 is 32 x 10^-3 mole3 . dm-. The maximum concentraion of A +2 ion is:
2 x 10^-3 mol.dm-3
Ksp values of four salts are given, which is more soluble in water:
10^-10
If “X” moles of Ag2CrO4 are dissolved in water to produce a saturated solution then Ksp will be:
4x^3
On the basis of Ksp, which sparingly soluble is least soluble in water:
Ksp = 2x10^-6
Which of the following reaction is the fastest?
Precipitation of BaSO4 by mixing two solution
For a reversible reaction, A➡B, which expression describes the rate of the forward reaction
-d[A]/dt
Consider the reaction PCl5 ➡ PCl3 + Cl2 in a closed container at equilibrium. At a fixed temperature, what will be the effect of adding more PCl5 on the equilibrium constant;
It remains unaffected
In 2HI ➡ H2 + I2, ΔH>0 the forward reaction is affected by change n;
Temperature
The reaction quotient (Q) for the reaction N2 + 3H2 ➡ 2NH3, the reaction will proceed from right to left is;
Q > Kc
Which value of Kc indicates the maximum yield of products
KC=10^22
The equilibrium constant for the reaction N2 + O2 ➡ 2NO is 4.4 x 10^-4 at 2000K temperature. In the presence of a catalyst, equilibrium is attained ten times faster. Therefore, the equilibrium constant in presence of a catalyst at 2000K is;
4.4 x 10^-4
The ratio of Kp/Kc for the reaction CO + 1/2 O2 ➡CO2 is:
(RT)^-1/2
For the reaction CO + Cl2 ➡COCl2, then Kp/Kc is equal to;
1/RT
For reaction PCl5 ➡ PCl3 + Cl2, unit of Kp is;
atm
2A + B ➡C. At equilibrium 0.20 mole of A, 0.45 mole of B and 0.15 molecular of C are present. Calculate Kc
8.3
4 moles of A are mixed with 4 moles of B. At equilibrium for the reaction A + B ➡C + D, 2 moles of C and D are formed, and the equilibrium constant for the reaction will be;
1
PCl5 ➡ PCl3 + Cl2 is in equilibrium, the concentration of PCl3 is doubled then the reaction will shift towards:
Let
The most suitable temperature for preparing ammonia gas is;
450°C
Which one is correct about the conjugate acid-base concept:
➡Conjugate base of a very weak acid is relatively very strong
➡Conjugate base of a very strong acid is relatively very weak
What is the conjugate base of OH-
O-²
Ostwald’s dilution law is applicable for:
Weak electrolyte
If the pKa of an acid is 5, the pKb of its conjugate base will be ___ at 25°C
9
The units of the ionic product of H2O are;
mol²/dm⁶
Which is the correct relation at 100°C
➡pH + pOH < 14
➡[H+][OH-] > 10-¹⁴
➡pKa + pKb < 14
The pH of a 10-⁴ molar solution of HX acid in water is:
4
What will be the pH of 1.0 mol dm-³of NH4OH, which is 1% dissociated
12
Which one of the following has the lowest pH values:
0.1 M HCl
Which one is the best buffer those have;
pH = pKa
An acidic buffer solution can be prepared by mixing:
Weak acid and its salt with a strong base
The pH of the buffer solution is 4.74, and the pKa of acid is 4.74. What is the ratio between the concentration of salt and acid:
1
If the concentration of salt is greater than the acid in the buffer solution, then the:
pH > pKa
The solubility of Fe(OH)3 is ‘x’ mole per dm^3. Its Ksp would be;
27x^4
Which one increases by common ion effect:
Solubility
In the reaction A2 + 4B2 ➡2AB4 such that ΔH < 0, the formation of AB4 will be favoured at:
➡Low Temperature
➡High Pressure
Consider the reaction PCl5 ➡ PCl3 + Cl2 in a closed container at equilibrium. At a fixed temperature, what will be the effect of adding more PCl5 on the equilibrium constant
It remains unaffected
The oxidation of SO2 to SO3 is an exothermic reaction. The yield of SO3 will be maximum if:
Temperature is reduced and pressure is increased
If the concentration of salt is greater than the acid in the buffer solution, then the
pH > pKa
In a saturated solution of AgCl, the molar concentration of Ag+ and Cl- is 1.0 x 10-5 M each. What is the value of Ksp?
1.0 x 10^-10
The solubility of Fe(OH)3 is ‘x’ mole per dm^3. Its Ksp would be:
27x^4
For the reaction H2 + I2 ➡2HI. The equilibrium constant changes with :
Temperature
The decomposition of N2O4 to NO2 is carried out at 280°C in chloroform. When equilibrium is reached, 0.2 moels of N2O4 and 0.02 moles of NO2 are present in 1:1 ratio. The equilibrium constant for the reaction N2O4 ➡2NO2 is;
0.002
In a given system, water and ice are in equilibrium, if the pressure is applied to the above system then;
More ice is melted
The solubility product of AgCl is 2.0 x 10^-10 mol²/dm⁶. The maximum concentration of Ag+ ions in the solution is:
1.41 x 10^-5 mol/dm³
An excess of silver nitrate is added to the aqueous barium chloride and the precipitate is removed from filtration. What are the main ions in the filtrate?
➡Ag+
➡NO3-
➡Ba+2
The pH of 10-⁴mole/dm³ of HCl
4
The most suitable temperature for preparing ammonia gas is:
450°C
The Kw of water is 25°C is given by:
10^-14
When HCl gas is passed through a saturated solution of rock salt, the solubility of NaCl
Decreases
For what value of Kc almost forward reaction is complete:
Kc=10^30
In which of the following equilibria will Kc and Kp have not the same value:
2SO2 + O2 ➡2SO3
The correct relationship between Kc and Kp can be written as:
Kp = Kc (RT)^Δn
If the temperature is increased the following reaction, then will go in;
N2 + 3H2 ➡2NH3
Exothermic Reaction
Reverse Direction
If the volume term is present in the denominator Kc expression, then which one is correct:
Increasing the pressure will shit the reaction backwards
The pH of an aqueous solution is 3.0 at 25°C. The hydrogen ion concentration in the solution would be;
0.001
Which one is a very weak acid:
H2O
Which one is correct about the conjugate acid-base concept;
➡Conjugate base of a very weak acid is relatively very strong
➡Conjugate base of a very strong acid is relatively very weak
Which one increases by common ion effect except:
Solubility
A basic buffer solution can be prepared by mixing;
Weak base and its salt with strong acid
Which one is the best buffer those have;
pH = pKa
The pH of the ideal buffer is:
7
If the ionic product is equal to Ksp, then the solution is;
Saturated
The solubility product is only applicable for that substance whose molar concentration is:
Less than 0.01
What will be the pH of 1.0 mol dm^-3 of H2X, which is only 50% dissociated
0
What will be the pH of 1.0 mol dm^-3 of NH4OH, which is 1% dissociated
12
Buffer solutions are used in except:
Qualitative Analysis
Buffer action can be explained by except:
Solubility Product
At equilibrium, the concentration of reactants and products are;
Constant
For N2 + 3H2 ➡2NH3, if Kc is 1 then the value of Kp at 273K would be:
1/(22.414)²
Which is correct relating to 100°C.
➡pH +pOH <14
➡[H+][OH-] > 10-¹⁴
➡pKa + pKb < 14
A basic buffer solution is:
➡NH4OH
➡NH4Cl
In the Haber process, the equilibrium mixture contains ____ NH3 by volume.
35%
For the following reaction in the gaseous phase
CO + 1/2 O2 ➡ CO2, Kc/Kp is:
(RT)^1/2
The equilibrium constant for the reaction N2 + O2 ➡ 2NO is 4.4 x 10^-4 at 2000K. In the presence o catalyst, equilibrium is attained then times faster. Therefore, the equilibrium constant in presence of a catalyst at 2000K is:
4.4 x 10^-4
What is the equilibrium expression for the reaction
P4(s) + 5O2(s) ➡P4O10(s)
Kc = 1/[O2]^5
The pH of 0.1M solutions of a weak acid is 3. The value of ionization constant Ka of acid is:
1 x 10^-5
pH=−log[H+]=3
Hence,[H+]=10−3M
[H+]=√c×Ka
For the reaction CO + Cl2 ➡COCl2, then Kp/Kc is equal to;
1/Rt
In a reaction CO + 2H2 ➡CH3OH. The concentration of hydrogen, carbon monoxide and methanol become constant at equilibrium, what will happen:
The equilibrium state remains undisturbed
Species acting both as bronsted acid and base is:
HSO4-1
What is the conjugate base of H2O
O-2
The conjugate base of H2PO4^-1 is;
HPO4^-2
The pH of an aqueous solution is 5.5. The hydroxyl ions concentration in the solution would be;
10^-8.5
pH + pOH=14
In 2HI➡H2 + I2 ΔH>0, the forward reaction is affected by a change in:
Temperature
In which case, Kp is less than Kc:
2SO2 + O2 ➡2SO3
For a homogenous reaction,
4NH3 + 5O2 ➡4NO + 6H2O
The units of equilibrium constant (Kc) is;
Conc +1
For a reversible reaction if the concentration of the reactants is doubled, then Kc will be:
The same
The molar solubility of sparingly soluble salt AB4 is “S” mol/dm^3, the corresponding solubility product Ksp is given in terms of Ksp by the reaction
S= (Ksp/256)^1/5
The Ksp of a salt having the general formula MX2 in water is 4 x 10^-12. The concentration of M+2 ions in an aqueous solution of the salt is;
1.0 x 10^-4 M
One of the following equilibriums is not affected by a change in the volume of the flask.
N2 + O2 ➡2NO
Which of the following is a base according to Bronsted Lowery’s concept :
I ^-1
With the increase in temperature, the ionic product of H2O
Increases
According to Lowery Bronsted concept, which of them is considered as an acid:
H3O+
the units of the ionic product of H2O are:
mole^2 dm^-6
On adding NH3 to water:
[H3O+] will decrease
Which one of the following has the lowest pH values:
0.1 M HCl
The pH of neutral water is 6.8 then the temperature of H2O is;
More than 25°C
The solubility of A2B3 is X mole/dm^3. Its Ksp is:
108X^5
A basic buffer solution can be prepared by mixing:
Weak base and its salt with strong acid
If the Kc value is small then the equilibrium position will shift:
Towards left
The value of Kc for H2O at 25°C is:
1.86 x 10^-16 moldm^-3
Ionization of KClO3 is suppressed by;
Adding KCl
4 moles of A are mixed with 4 moles of B. At equilibrium for the reaction A + B ➡C + D, 2 moles of C and D are formed, the equilibrium constant for the reaction will be;
1
Select the pKa values of the strongest acid from the following:
1
Which of the following is not favourable for SO3 formation, 2SO2 + O2 ➡ 2SO3
Exothermic Reaction
High temperature
The reaction quotient (Q) for the reaction N2 + 3H2 ➡2NH3, the reaction will proceed from right to left is:
Q > Kc
According to the Lowery Bronsted concept, the correct order of relative strength of bases follows the order;
OH- > CH3COO- > Cl-
Which value of Kc indicates the maximum yield of products?
Kc = 10^2
The pH of 1M MOH solution which is only 10% dissociated
13
The addition of a catalyst to a chemical reaction will bring about a change in which of the following characteristics of the reaction
Activation Energy
The rate constant or forward and backward reaction of hydrolysis of the ester is 1 x 10^-2 and 2 x 10^-3 respectively. The Kc of reaction is;
5
1 moel of ethyl alcohol was treated with one model of acetic acid at 25°C. 2/3rd of acid changes into ester at equilibrium. The equilibrium constant of the reaction will be;
4
The equilibrium expression for a reaction is Kc=X^2/V(a-X), which is true for this reaction:
Decrease of pressure favoured forward reaction
Which of the following depends upon temperature?
➡Kw + Kc
➡Ka + Kb
➡Ksp
If the pKa of an acid is 5, then the pKb of its conjugate base will be ___ at 25°C.
9
For the following gases equilibrium, N2O4 ➡2NO2 at STP. Kp should be equal to:
22.414 Kc
The value of Kw in an acidic aqueous solution at 298K is;
10^-14
For acidic buffer, pH < pKa if:
[salt] < [acid]
Which is the correct statement:
➡pKa x pKb = 14❌
➡Ka x Kb = pKw❌
➡pKa + pKb = Kw❌
➡Ka x Kb = Kw✅
For the following reacton in the gaseous phase
CO + 1/2O2 ➡CO2, Kc/Kp is:
(RT)^1/2
The equlibirum constant for the reaction N2 + O2 ➡2NO is 4.4 x 10^-4 at 2000K temperature. In the presence of catalyst, equilibirum is attained ten times faster. Therefore, the equilibirum constant in presence of catalyst at 200K is:
4.4 x 10^-4
What is the equilibrium expression for the reaction:
P4(s) + 5O2(g) ➡P4O10(s)
Kc= 1/[O2]^5
pH of 0.1M solution o fweak acid is 3. The value of ionization constant Ka of acid is:
1 x 10^-5
For the reaction CO(g) + Cl2 ➡COCl2 (g) , then Kp/Kc is equal to:
1/RT
In a reaction CO (g) + 2H2 (g) ➡CH3OH (g) ΔH=-92 kJ/mol. The concentration of hydrogen, carbon monoxide, and methanol becomes constant at equilibrium, what will happen:
Equilibrium state remains undisturbed
The reaction involving H3PO4^-1 are given below:
(i) H3PO4 + H2O ➡H3O ^+ + HPO4^-1
(ii) H2PO4^-1 + H2O ➡HPO4^-2 + H3O^+
(iii) H2PO4^-1 + OH- ➡H3PO4 + O^-2
In which of above does H2PO4^-1 act as an acid.
(ii) only
Species acting both as Bronsted acid and a base is;
HSO4 ^-1
What is the conjugate base of OH-:
O^-2
The conjugate base of H2PO4^-1 is:
HPO4^-2
pH of a aqueous solution is 5.5. The hydroxyl ions concentration in the solution would be:
-8.5
In 2HI➡H2 + I2 ΔH > 0, the forward reaction is affected by change in:
Temperature
In which case, Kp is less than Kc:
2SO2 + O2 ➡2SO3
For a homogenous reaction
4NH3 + 5O2 ➡4No + 6H2O
The units of equilibrium constant (Kc) is:
Conc. ^+1
For a reversble reaction if the concentration of the reactants are doubled, the Kc will be:
Same
The molar solubility of sparingly soluble salt AB4 is “S” mol/dm^3, the corresponding solubility product Ksp s given in term of Ksp by the reaction
S=(Ksp/256)^1/5
The Ksp of a salt having general formula MX2 in water is 4 x 10^-12. The conc. of M+2 ions in aqueous solution of the salt is:
1.0 x 10^-4 M
One of the following equilibrium, is not affected by change in volume of the flask.
N2 + O2 ➡2NO
A certain buffer solution contains equal conc. of X and HX. Ka for HX is 10^-8. The pH of buffer is:
8
Which of the following is a base according to Lowery Bronsted concept?
I^-1
With increase in temperature, ionic product of H2O:
Increases
According to Lowery Bronsted Concept, which of the following is considered as an acid?
H3O +
The units of onic produt of H2O is:
Mole^2 dm^-6
On adding to NH3 to water:
[H3O+] will decrease
Which one of the following has the lowest pH values:
➡0.1M HCl✅
➡0.01M HCl❌
➡0.1M KOH❌
➡0.01M KOH❌
Which Henderson equation is not correct?
➡pH = pKₐ - log([acid]/[salt]
➡pH = pKₐ + log([salt]/[acid]
➡pH = pKₐ - log([salt]/[acid]
The pH of neutral water is 6.8 then the temperature of H2O is:
More tha 25°C
The solubiity of A2B3 is X moledm^-3. Its Ksp is:
108X^5
A basic buffer solution can be prepared by mixing:
Weak base and its salt with strong acid
If Kc value is very small then equilbirum position will shift:
Towards Left
The value of Kc for H2Oat 25°C is:
1.86 x 10^-16 mol/dm^3
Ionization of KClO3 is suppressed by:
Adding KCl
4 moles of A are mixed with 4 moles of B. At equilibrium for the reaction A + B ➡C + D are formed, the equilibrium constant for reaction wll be:
1
Select the pKa values of strongest acid rom following:
1
Which of the following is not favourable for SO3 formation,
2SO3 + O2 ➡2SO3 ΔH=-45kcal
High Temperature
The reaction quotient (q) for the reaction N2 + 3H2 ➡2NH3 is given by Q=[NH3]^2/[N2][H2]^3, the reaction will proceed from right to let is:
Q > Kc
According to Lowery Bronsted concept, correct order of relative strrength of bases follows the order:
OH- > CH3COO- > Cl-
Which value of Kc indicate maximum yield of products
Kc = 10^2
The pH of 1M MOH solution which is only 10% dissociated:
13
Addition of catalyst to a chemical reaction will bring about a change in which of the folwing characterstics of reaction.
1. Activation Energy 2. Enthalpy Change 3. Value of equilibrium constant
- Only
The rate constant for forward reaction and backward reaction of hydrolysis of ester are 1x 10^02 and 2x 10^03 respectively. The Kc o reaction iS
5
1 mole of ethyl alcohol was treated with one mole of acetic acid at 25°C. 2/3 rd of acid changes into ester at equilibrium. THe equilibrium constant of the reaction will be:
4
The equilibirium expression for a reaction is Kc=X^2/V(a-X), what is true or this reaction.
Decrease of pressure favoured forward reaction
Which of the following depends upon temperature.
➡Kw + Kc
➡Ka + Kb
➡Ksp
If pKa of an acid is 5, then pKb of its conjugate base wll be ___ at 25°C.
9
For the following gases equilibirum. N2O4 ➡2NO2 at STP. Kp should be equal to:
22.414Kc
The value of Kw in an acidic aqueous solution at 298K is:
10^-14
For acidic bufer, pH < pKa if:
[salt] < [acid]
What is correct statement:
Ka x Kb = Kw
For reaction PCl5 ➡PCl3 + Cl2 Unit of Kp is:
atm
In the reaction A2 + 4B2 ➡2AB4 such that ΔH < 0, the formato of AB4 will be favoured by:
➡Low Temperature
➡High Pressure
Consider the reaction PCl5 ➡PCl3 + Cl2 in a closed container at equilibrium. At a fixed temperature, what wil be the effect of adding more PCl5 on the equilibirum constant
It remains unaffected
The oxidation of SO2 to SO3 is exothermic reaction. The yield of SO3 will be maximum f:
Temeprature is reduced and pressure is increased
If the concentration of salt is greater than the acid in buffer solution, then the:
pH > pKa
In a saturated soluton o AgCl, the molar concentration of Ag+ and Cl- is 1.0 x 10^-5M each. What is the value of Ksp.
1.0 x 10^-10
The soubility of Fe(OH)3 x ‘x’ mole per dm^3. ts Ksp would be:
27x^4
For the reaction H2 + I2 ➡2HI. The equilibrium constant changes with:
Temperature
The decomposton of N2O4 to NO2 is carried out at 280°C in chlorofoam. When equilibrium is reached, 0.2 moles of N2O4 and 0.02 moles of NO2 are present in 1:1 rato,. The equilibirum constant for the reaction N2O4➡2NO2 is:
0.002
In a given system, water and ice are in equilibrium, if the pressure is applied to the above system the:
More ice is melted
The solubility product of AgCl s 2.0 x 10^-10 mol^2 dm^-6. The maximum concentration of Ag+ ions in the solution is:
1.41 x 10^-5 mol dm^-3
An exces of silveer nitrate is added to the aqueous barium chloride and the preciptate is removed by filtration. What are tha
An exces of silver nitrate is added to the aqueous barium chloride and the preciptate is removed by filtration. What are the main ions in the filtrate.
Ag+ and No3- and Ba+2 only
pH of 10^-4 moledm^-3 of HCl
4
The most suitable temperature for preparing ammonia gas is;
450°C
The Kw of water at 25°C is given by:
10^-14
When HCl gas is passed through saturated solution of rock salt, the solubility of NaCl:
Decreases
For what value of Kc almost forward reaction is complete
Kc = 10^30
In which of the following equilibria will Kc and Kp have not the same value
2SO2 + O3 ➡2SO3
Correct relationship b/w Kc and Kp can be written as:
Kp = Kc(Rt)^Δn
If the temperature is increased of folowing reactio, then wll go in
N2 + 3H2 ➡2NH3 ΔH=-ve
Reverse Direction
If the volume term is present in denominator of Kc expression, then whch one is correct:
Icrease in pressure will shift the reaction backward
Which statement is incorrect:
➡pH and [OH-] are inversely related to each other❌
➡pOH and [OH-] are inversely related to each other❌
➡pH and [OH-] are directly related to each other✅
➡pOH means potential of hydroxyl ion concentration ❌
pH of an aqueous soluton is 3.0 at 25°C. The hydrogen ion concentration in the solution would be:
0.01
Which one is very weak acid
H2O
Which one is correct about conjugate acid-base concept?
➡Conjugate base of a very weak acid is relatively very strong
➡Conjugate base of a very strong acid is relatively very weak
Which one increases by common ion except?
➡Solubility✅`
➡Crystallization❌
➡Association of ions❌
A basic buffer solution can be prepared by mixing:
Weak base and its salt with strong acid
Which one is best buffer those have:
pH = pKa
The pH of of ideal buffer is:
7
If ionic product is equal to Ksp, then the soluton is:
Saturated
The solubility product is oly appicable for those substances whose molar concentratons is:
Less than 0.01
What wll be the pH of 1.0 mol dm^-3 o H2X, which is only 50% dissociated:
0
What will be the pH of 1.0 mol dm^-3 of NH4OH, which is 1% dssociated
12
Buffer soluton are used in except:
Qualitative analysis
Buffer action can be explained by except:
➡Common ion Effect❌
➡Le-Chatelier’s Principle❌
➡Law o mass action❌
➡Solubiity Product✅
At equilibrium, the concentration of reactants and products are:
Constant
For N2 + 3H2 ➡2NH3, if Kc is 1 than value of Kp at 273 K would be:
1/(22.414)^2
Which in correct relating at 100°C
➡pH + pOH <14
➡pKa + pKb <14
➡[H+][OH-] > 10^-14
Expression of solubiity product constant (KsP) or following sparingly soluble salt is:
AxBy ➡xA^+y + yB^-x
[A^+y]^x[B^-x]^y
Basic buffer soluton is
NH4OH/NH4Cl
In Haber process, equilibrium mixture contains ___ NH3 by volume.
35%
For exothermic reaction, the minimum value for the energy of activaton will be:
More than ΔH
The units of equilibrium constant for the reacton 2SO3➡ 2SO2 + O2 are:
mol. dm^-3
The value of ionic product tells us about the nature of solution, precipitation occurs when:
Ksp < Ionic Product
Select the buffer which is not acidic:
NH4OH and NH4NO3
A buffer is prepared by mixing the solutions of 1M acetic acid and 0.5M sodium hydroxide. The pH should be equal to:
Less tha pKa of acid
If number of moles of reactants are greater to those of products, then relationship between Kp and Kc is:
Kp < Kc
Yield of ammonia in Haber’s process can be increased by all except:
Adding catalyst
Difference of energy between product and transition state is called:
Enthalpy of reaction
The equilibrium constant for the reaction 2O3 ➡ 3O2 at 25°C, this indicates that:
[O3] < [O2]
Determine partial pressure of NO at equilbiirum if partial pressure of N2 adn O2 are 8 ad 32 torr respectively.
N2 + O2 ➡2NO
16 torr
Find the Kc of followign reaction if equilibrium concentration of acetic acid,ethanol, ethyl acetate and water are 1.5M, 1.5M, 2.5M, and 2.5M respectively.
CH3COOH + CH3CH2OH ➡CH3COOCH2CH3 + H2O
2.77
An addition of NH4Cl in NH4OH solution suppresses the concentration o:
OH-
Following is the condition of reversible reaction that is not affected by pressure
Δn = 0
Catalyst can change:
Activation Energy
pH of buffer in which concentrations of salt and base are 0.1M and 0.01M respectively. (pKb=4.0)
9.0
Equilibrium position is shited backward by increasing temperature in all except:
N2 + O2 ➡2NO
Ksp for following can be written as PbCl2 ➡Pb+2 + 2Cl-
[Pb+2][Cl-]2
The solubility product of PbSO4 is 4 x 10^-6 mol^2.dm^-6. The maximum concentration of Pb+2 ions is:
2 x 10^-3 mol.dm^-3
Rate of exothermic reaction is increased by increasing all except:
Volume of vessel
Following is an exothermic reaction A + B ➡C + D. Which is correct statement?
Rate of reaction will increase by increasing temperature
At equilibrium, relationship between concentrations of reactants and products:
➡[Reactants] > [Products]
➡[Reactants] < [Products]
➡[Reactants] = [Products]
For the gas phase reaction A + B ➡C + D one starts with 6 moles A and 7 moels B per dm^3. When equilbirum is attained, 4.5 moels of C and 4.5 moles of D are formed, waht is the value of Kc for the reaction
5.4
Potenital Energy of activated complex for exothermic reaction is:
Greater than reactants
Unit of slope in Arrhenus equation is:
Kelvin
Solubility product of a salt AB is 0.25 mol^2/dm^6, what will be its solubility
0.5
In arrhenus equation k=Ae^-Ea/RT, ___ depends upon collison frequency.
A
1.0g mole of ethyl alcohol and 1.0g mole of acetic acid are ixed. At equilibrium 0.333g mole of the ester is present. The value of equilibirum constant is:
1/4
Consider a reaction N2 + 3H2 ➡2NH3. Correct relation between Kp and Kc is
Kp =Kc (RT)^-2
Approximate units of Kp for the following reaction is
2SO3 ➡2SO2 + O2
Torr
CG3COOC2H5 + H2O ➡CH3COOH + C2H5OH
Unit of rate of this reaction is:
mol.dm^03 .s^1
Ionization of phenol can be decreased by adding:
Hydrochloric acid
If Ksp is greater than the product of concentration of ions at particular temperature, then solution is:
Unsaturated
In which case, decrease of pressure favours forward reaction:
PCl5 ➡PCl3 + Cl2
The rate of reaction can be increased in general by all of the following factors except:
By Increasing activation energy
At equilibirum:
➡Rf=Rb
➡Conc. of the reaction mxutre becomes constant
➡Conc.-time graph bceomes parallel to time axis
Ratio of Kc/Kp for the reaction is:
N2 + 3H2 ➡2NH3
(RT)^2
PCl5 ➡PCl3 + Cl2 is atequilibirum, the concentration of PCl3 is icnreased then reacton with shift towards ___ and Kc ___.
➡Left
➡Remain same
For reacton N2 + 3H ➡2NH3 unit of Kp is:
atm^-2
2X + Y ➡Z. At equilibirum 0.20 mole of X, 0.45 mole of Y and 0.15 mole of Z are present. Calcualte Kc:
8.3
Which of the following expression is correct for 2SO2 + O2 ➡2SO3
➡Kp = Kc(Rt)^-1
➡Kp = Kc/(Rt)
➡Kc = Kp(Rt)
The most suitable conditions for preparng ammonia gas by Haber’s process are:
Fe, 200atm and 450°C
In a gaseous reaction, moles of products are greater than reactants and reacton is endothermic, waht are the conditons that can be applied to get amximum yield
Suitable Catalyst, High Temperature and Low Pressure
For which of the following reactions, Kp=Kc
H2 + F2 ➡2HF
The equilbirum expression for reaction is Kc=4x^2/(a-x)V for a gaseous phase reaction the number of moles of product are __ reactatns.
Greater than
Which of the following solution cannot act as buffer solution
HCl + NaCl
The buffer with amximum capacity will be:
➡pH = pKa
➡[Salt] = [Acid]
If the concentrationn of salt is greater than the acid in buffer solution, then:
pH > pKa
pH of buffer is ___ if [acid]=0.19M and [salt]=1. and pKb=9.26
4.74
(pKa + pKb=14)
A + B ➡C + D in this reaction, at equilibrium if [A]=2.5M, [B]=3.2M, [C]=5M and [D]=4M, Calcualte the Kc for this reaction:
2.5
The solubility of AlCl3 is ‘s’ mole per dm^3. Its Ksp would be:
27s^4
BiCl3 reacts with water to form artifical milk (BiOCl) and HCl, by dilution of reacto mixture ___.
More artifical milk formed
The value of equilibrium constant Kc for the reaction 2HF➡H2 + F is 10^-13 at 2000°C, calculate the value of Kp for the reaction:
10^-13
A buffer solution is that which resists/minimizes the change in:
pH
If in AgCl solution, some salt of NaCl s added, AgCl will be preciptated due to:
Common Ion Effect
Formation of NH3 is reversible and exothermic process, what will happen on cooling?
More amount of reactants will be converted into the product
Preciptation of table salt (NaCl) by passing HCl gas thorugh its saturated aqueous solution is an example of:
Common Ion Effect
If Kc value is very large then equilbirium position lies:
Towards Right
Following is an exothermic reaction, which is correct statement?
A + B ➡C ΔH=-ve.
Rate of reaction will icnrease by increasing temperature
