UNIT#07 REACTION KINETICS Flashcards
Which one of the following is correct about the following reaction if iron is not 100% pure?
Very slow reaction
Which of the following reactions is usually slow?
Organic substitution reaction
For a chemical reaction to occur?
Reacting molecules must be properly oriented and energy and energy more than or equal to Ea
The increase in reaction rate as a result of an increase in temperature from 10K to 100K is;
512
(➡2^ΔT/10)
By increasing the concentration of reactant,s the rate of reaction____
Increases
The rate of a reaction involving ions can be studied by:
Electrical Conductivity Method
Which method for rate determination is applicable to reactions in solutions, where there are changes in refractive indexes of the substances taking part in the chemical reaction:
Refractometric method
The specific rate constant of a chemical reaction is the rate of the reaction when the concentration of the reactant is;
Equal to unity
The unit of the rate constant of second order reaction is;
mole-1 dm+3 sec-1
The 2nd order reaction becomes 1st order when:
One of the reactants is in large excess
The half-life time for a 1st order decomposition of a substance dissolved in CCl4 is 2.5 hours at 30°C. The amount of substance left after 10 hours if the initial weight of a substance is 160g.
10g
(Number of half-life=Total Time/Half-life)
Hydrolysis of ethyl acetate into acetic acid and ethanol in the presence of mineral acid is
Pseudo 1st Order Reaction
For a reaction A + 2B ➡C, the rate is given by Ratek[A][B], hence the order of the reaction is;
2
For a chemical reaction A➡B, the rate of reaction doubles when the concentration of A is increased four times. The order of reaction for A is;
Half
What will be the order of reaction if doubling the concentration of a reactant increases the rate by a factor of 4 and tripling the concentration of a reactant by a factor of 9
2
The rate law of a reaction is, rate= k[A]2[B]. On doubling the concentration of both A and B, the rate of reaction increases ___ time.
8
For the reaction A + B➡C+D, doubling the concentration of both the reactants increases the reaction rate by 8 times and doubling the initial concentration of only B simply doubles the reaction rate. The rate law for the reaction is;
Rate=k[A]2[B}
The rate of reaction 2X+Y➡Product
Rate=k[X]2[Y] if X is in large excess, the order of the reaction is;
1st
For the 1st order decomposition reaction, 2N2O5➡2N2O4 +O2 the half-life is given by:
0.693/k
The half-life period of zero order reaction is equal to;
a/2K
(➡For zero order reaction, half-life period is directly proportional to the initial concentration of reactants)
For which of the reaction, the half-life is inversely proportional to the initial concentration of reactants
2nd Order
If ‘a’ is the initial concentration of the reactant then the half-life period of the reaction of nth order is directly proportional to;
a^1-n
For the first-order reaction, the half-life is 14 sec. The time requires for the initial concentration to reduce to 1/8th of its value to:
42 sec
The rate constant of a reaction is 3x10^03 moldm^-3sec^-1. The order of reaction is;
0
The activation energy of the reaction
Required for effective collision
Ea appears as a potential energy hill between ___ for carrying out the reaction.
Reactants and the Products
If Ef and Er are the activation energies of forwarding and reverse reactions. The reaction is known to be exothermic then:
Ef < Er
For an endothermic reaction A➡B, the activation energy of the forwarding reaction is 15 kcal mol-1 and the enthalpy change of a reaction is 5 kcal mol-1. The activation energy for reverse reaction B➡A is:
10 kcal mole-1
Which one is the assumption o collision theory of reaction rate?
➡During a chemical reaction the particles must collide
➡Reaction between the colliding particles can only take place if upon collision theory
➡Only those collisions are effective and take place in the proper orientation
If the energy of the activated complex lies close to the energy of reactants, it means that the reaction is;
➡Exothermic
➡Fast
The activation energy for a simple chemical reaction A➡B is Ea in the forwarding direction. The activation energy for reverse reaction;
➡Can be less than
➡More than Ea
When the potential energy of the transition state is very high, then which one of the following results is applicable
➡High activation energy
➡Slow Reaction
Which of the following best explains the effects of a catalyst on the rate of a reversible reaction
It provides a new reaction path with a lower activation energy
What is the correct relation between rate and activation energy
Rate ∝ 1/ Ea
Concentrated sugar solution undergoes hydrolysis into glucose and fructose by an enzyme:
Invertase
Which of the followings is correct about enzyme catalysts
➡These are in the pure crystalline state
➡The activity of enzyme catalyst is inhibited by poison
➡Enzyme catalytic reaction has the maximum rate at optimum temperature
The reaction rate in the forwarding direction decreases with the passage of time because:
The concentration of reactants decreases
An activated complex is formed due to;
Effective collision
The chemical reactivities of elements depend upon their characteristics electronic:
Configurations
Activated Complex has;
High Potential Energy
Catalyst can:
Increase the rate of reaction
The rate of reaction in gases is best described as:
Δp/Δt
The energy required to start a reaction is called;
Activation energy
The number of reacting molecules which changes their concentration chemical change is called;
Order of reaction
Drawing a graph between concentration change with time gives a:
Parabola
Rate = k[NO2], the order of this reaction is;
One
With the passage of time rate of reaction always;
Decreases
Hydrolysis of tertiary butyl bromide is:
Pseudo First Order
If a graph is plotted with concentration data of a reaction in a chemical reaction the curve is;
Falling
Spectrum is the visual display or ___ of component of white light when it is passed through a prism.
Dispersion
After one half-life, the mass of the substance becomes;
Half
The activated state is:
➡Least Stable
➡Most Energetic
In spectrometry, the spectrometer can analyze
Atom
The change in volume depends on:
Initial and Final states
When the rate o reaction is measured by the amount of radiation absorbed, it is called;
Spectrometry
If the time interval is very small for determining the rate of reaction the values of the average and instantaneous rate
Very close to each other
As reaction starts instantaneous rate is:
Higher than the average rate
The activated complex is a reaction that has;
PE max
When the colliding molecules come closer to each other. It _____ to go to transition :
Slows down
The half-life period for a first-order reaction is independent of;
The initial concentration of the compound
The reaction which is completed in steps must contain;
➡Rate determining step
➡Slowest Step
Specific rate constant is also called
Velocity constant
For third order reaction, rate cosntant has units:
mol^-2 dm^6 s^-1
(concentration)^n-1
Slowest step in the reaction is called:
Rate determining step
A certain reaction has the rate equation, Rate=k[A][B]2. The rate is 2.5x10^-3 mol dm-3s-1. When [A] is 0.2 mol dm-3 and [B] is 0.050 mole dm-3. Calculate the numerical value of the rate constant.
5.0
The units of second order rate constant are usually expressed as:
mol-1 dm3 s-1
The rate expression of a reaction is, Rate = k[A][B]2. What happens to rate of reaction if concentrations of A and B are doubled?
Increased eight times
One of the following is not a physical method for determination of rate of reation;
Titrimetry
Dilatometric method is useful for the reaction that involves:
small volume change in solution
Which property of liquid is measured by polarimeter
Optical Activity
Generally by increasing temperature rate of chemical reaction increase. It is due to;
Greater number of molecule having activation energy
Arrhenius equation describes the effect of:
Temperature on rate of reaction
Following is an exothermic reaction. Which is correct statement:
➡Rate of reaction will increase by increasing temperature
Which of the followings is pseudo first order reaction:
➡Acid Catalyzed hydrolysis of an ester
➡Hydrolysis of tertiary butyl bromide
In Rate=k[A][B] the second order reaction becomes _____ if [A] is in large excess
Pseudo First Order
For a reaction like X + 2Y ➡Z Rate=k[X]0[Y]2
If concentration of X and Y is doubled, then rate of reaction increase
4 times
On increasing the temperature ,the rate of reaction increases mainly because;
Collision frequency increases
The collision frequency is:
Proportional to the concentration of reacting molceuls
Which statement is incorrect about activated complex
➡Short Lived❌
➡Maximum Energy❌
➡Unstable combination of atoms❌
➡Less energy than Ea✅
In a reaction 2X+Y ➡M+N
If the concentration of Y kept constant and that of X is tripled. The reaction will be;
increase 9 times
A reaction has equal activation energy for forward and backward reaction. Which statement is coorect:
➡Reaction is zero order❌
➡Enthalpy change is zero✅
➡Product has less energy than reactants❌
➡No Catalyst has been used❌
The number of colliding molecules of different gases calculated from kinetic theory of gases is of magnitude of ___ per litre per second.
10³²
The value of activation energy of chemical reaction is primarily determine by:
Number of collisions per unit time
The value of activation energy is primarily determined by:
Effective Collision
For endothermic reaction, Ea is activation energy in Kj/mole. The maximum value of enthalpy of reaction (ΔH) will be:
Less than Ea
Which is the correct expression of Arrhenius equation;
k = Ae^-Ea/RT
The number of atoms or molecules whose concentration determines the rate of a chemical reaction is called the;
Order of the reaction
The order of reaction may be determined by;
➡Differential
➡Half-Life Method
➡Graphical Method
If rate constant for any reacton is equal to rate of reaction at all concentration. Then the order of reaction will be;
Zero
The rate for the reaction is:
Rate = k[A][B]2/3.
The order of reaction is;
5/3
Factor which does not generally affect the rate of reaction;
Pressure
The rate of chemical reaction roughly doubles for every 10°C rise of temperature. If temperature is raised by 20°C, the rate may become;
4 times
The units of slope are in:
Per Kelvin
The rate of reaction can be increased i general by all of the following factors except:
By increasing activation energy
The rate of reaction decreases how many times when tempearture drops rom 150K to 120K
Eight
Rate of chemical reaction increase rapidly even for small increase in temperature because of rapid increase in the:
Fraction of molecuels with energy more than activation energy
Which will change for first order reaction with time:
Rate of reaction
All are slow processes except:
Reaction of AgNO3 with NaCl
(Ionic solutions react astly)
On the basis of given values Ksp, which sparingly soluble salt is least soluble in water:
Ksp = =2x 10^6
If “X” moles of Ag2CrO4 are dissolved in water to produce a saturated solution then Ksp will be:
4x3
Ksp values of four salts are given, which is more soluble in water:
10^-10
(Greater the Ksp, Greater the solubility of salt)
The solubility product of an ionic compound AB2 is 32 x 10^-9 mol3 dm-9. The maximum concentration of A+2 ion is:
2 x 10^-3 mol. dm-3
AgNO3 + NaCl ➡AgCl + NaNO3 , which one is correct about a given reaction;
It is a very fast reaction
The unit of the rate constant is the same as that of the rate reaction in
Zero order reaction
The rate of reaction is doubled for every 10°C rises in temperature. The increase in reaction rate as a result of temperature rise from 10°C to 100°C is;
512
The mathematical relation between the rate of reactions and the concentration of the reactants is known as the
Rate Law Equation
AgNO3 + NaCl ➡AgCl + NaNO3, which one is correct about given reaction.
It is a very fast reaction
The unit of the rate constant is the same as that of the rate of reaction in:
Zero order Reaction
The rate of reaction is doubled for every 10°C rises in temperature. The increase in reaction rate as a result of temperature rise from 10°C to 100°C is;
512
The mathematical relation between the rate of reaction and the concentration o the reactants is known as the:
Rate law equation
If 75% of any given amount of radioactive element disintegrates in 60 min. The half-life of a radioactive element is:
30 min
(k= 2.303/t log 100/100-x
t1/2 = 0.693/k)
The energy of activated complex is:
➡Greater than reactants
➡Greater than products
The rate of reaction depends upon:
Molar concentration
For a first-order reaction, the half-life period is independent of;
Initial Concentration
If the rate of the reaction is equal to the rate constant, the rate of reaction is:
0
Which of the following is incorrect about the rate of reaction?
➡It is calculated experimentally❌
➡It is the sum of powers of concentration in the rate law equation❌
➡The order of reaction cannot be fractional✅
➡There is not necessarily a connection between order and stoichiometry of a reaction❌
For the reaction A+B+C ➡Product, Rate =k[A]^1/2 [B]^1/3 [C]. The order of the reaction is:
11/6
The half-life period of a first-order reaction is 15 minutes. The amount of substance left after one hour will be:
1/16
For an exothermic reaction, the activation energy of the forward reaction is 70kJ/mol and the enthalpy change of a reaction is 30 kJ/mol. The activation energy for the reverse reaction is;
100 kJ/mol
According to Arrhenius’s equation, a straight line is to be obtained by plotting the logarithm of the rate constant against.
1/T
A mixture of H and Cl2 will react twice as fast if the partial pressure of H2 or Cl2 is
Increase from 0.5 to 1atm
Select the suitable catalyst for the given reaction:
HCOOH ➡ H2O + CO2
Cu
The equilibrium expression or reaction is Kc= 4x^2 V / (a-2x)^2(b-x) for a gaseous phase reaction, then which of the following is true?
Kp < Kc
In the given 2A + B ➡Products, it is observed on quadrupling the concentration of B, the rate is increased 16 times. The order of reaction with respect to B is;
2
The rate of reaction A+B+C ➡Products is given by Rate=k[A][B]^0[C]. If A is in excess, the order of reaction would be:
1
A reaction is first order with respect to A and second order with respect to B. The rate equation is;
Rate = k[A][B^2]
If the half-life for a particular reaction is found to be constant and independent of the initial concentration of the reactant then the reaction is of:
1st Order
What is the half-life period of a given reaction when the initial concentration of HI is 0.050 M and the rate constant ‘k’ is 0.080 dm^3mol^-1sec^-1
250 sec
(It’s an overall 2nd order reaction
Half-Life = 1/ka
t½ = 1/(0.050)(0.080)
t½=1/4×10^-3
t½=250
What will be the first half-life period of 1st order reaction, if the value of rate constant is ‘k’ is 0.3465 min^-1
2.0 minute
What will be the rate constant for 2nd order reaction, when the rate of reaction is 4 moles dm^-3 sec^-1 and the concentration of A is equal to the concentration of B which is 0.1 moles dm^-3?
400 mole^-1 dm^+3 sec^-1
Which method for the rate determination is applicable if a reactant or a product absorbs UV/ visible or IR radiations?
Spectrometric Method
What will be the rate of reaction, when a change in concentration of a substance is 3 x 10^-3
3 x 10^-4 mol dm^-3 sec^-1
The unit of the rate constant of 1st order reaction is:
sec-¹
The activation energy of a reaction:
Is in addition to the average KE of the products
Ea appears as a potential energy hill between ____ or carrying out the reaction.
Reactants and the Products
The Slope of the graph between 1/T and log k gives:
➡Reaction rate
➡Activation energy
➡Specific Rate Constant
The unit of the rate constant is the same as that of the rate of reaction is;
Zero order reaction
Arrhenius equation can be used for evaluating:
Activation Energy
A catalyst can:
➡Accelerate the reaction rate
➡Retard the reaction rate
➡Chemically un-consumed at the end of the reaction
The 2nd order of reaction becomes 1st order when:
One of the reactants is in large excess
Oxidation of SO2 in the presence of NO catalyst is an example of:
Homogenous catalysis
Which one of the following is not a characteristic of a catalyst:
➡It is specific in its action❌
➡Provides the reactants with a low activation energy❌
➡Becomes chemically changed at the end of a reaction✅
➡It can be poisoned by an impurity which deactivates its catalytic capability❌
The specific rate constant of a chemical reaction is the rate of the reaction when the concentration of the reactant is:
Equal to unity
The half-life time for a 1st order decomposition of a substance dissolved in CCl4 is 2.5 hours at 30°C. The amount of substance left after 10 hours if the initial weight of a substance is 160g.
10 g
An endothermic reaction A➡B has an activation energy of 15 kcal/mol and the heat of the reaction of 5 kcal/mol. The activation energy for reaction B➡A will be:
10 kcal/mol
The rate of reaction is doubled for every 10°C rises in temperature. The increase reaction rate as a result o temperature rise from 10°C to 100°C is:
512
For the 1st order decomposition reaction 2N2O5 ➡4NO2 + O2, the half-life is given by:
0.693/k
Which one of the following is correct about the following reaction if iron is not 100% pure:
2Fe + 3H2O ➡ Fe2O3.3H2O
Very slow reaction
For a chemical reaction to occur
Reacting molecules must be properly oriented and energy more than or equal to Ea
The reaction that involves gases, its rate does not depend upon:
Concentration
The mathematical relation between the rate of reaction and the concentration of the reactants is known as the:
Rate law
Which one affects the specific rate constant:
Temperature
When the concentration o reactant in the reaction is increased by 8 times, the rate increased only by 2 times. The order of the reaction is;
1/3
If 75% of any given amount of radioactive element disintegrates in 760 min. The half-life of radioactive elements is:
30 min
The unit of the rate constant of second order reaction is:
mole^-1 dm ^+3 sec^-1
The half-life period of zero order reaction is equal to:
a/2K
If the energy of the activated complex lies close to the energy of reactants, it means that:
➡Exothermic
➡Fast
Which of the following statements regarding a catalyst is not true:
➡A catalyst does not alter the equilibrium in a reversible reaction❌
➡A catalyst can initiate a reaction which is not thermodynamically favourable❌
➡Catalytic reactions are very specific in nature❌
➡A catalyst remains unchanged in composition and quantity ✅
Radiations are absorbed in:
Refractormetric Method
Hydrolysis of ethyl acetate into acetic acid and ethanol in the presence of mineral acid is:
Pseudo 1st Order Reaction
When the potential energy of the transition state is very high, then which one of the following results is applicable?
➡High Activation Energy
➡Slow Reaction
The energy of activated complex is:
Less than reactants
The activation energy for a simple chemical reaction A➡B is Ea in the forward direction. The activation energy for the reverse reaction:
Can be less than or more than Ea
For a reaction A + 2B ➡C, the rate is given by k[A][B], hence the order of the reaction is;
2
The rate of reaction depends upon:
Molar Concentration
For a first-order reaction, the half-life period is independent of :
Initial Concentration
The activation energy of a chemical reaction can be determined by:
Evaluating velocities of a reaction at two different temperature
If the rate of the reaction is equal to the rate constant, the order of the reaction is;
0
Which of the following best explains the effects of catalyst on the rate of a reversible reaction?
It provides a new reaction path with a lower activation energy
For a chemical reaction A ➡B, the rate of reaction doubles when the concentration of A is increased four times. The order of reaction for A is;
Half
Among the following factors, the specific reaction rate of a first-order reaction
Temperature
Which of the following is incorrect about the order of a reaction:
➡It is calculated experimentally❌
➡It is the sum of powers of concentration in rate law expression❌
➡The order of reaction cannot be fractional✅
➡There is not necessarily a connection between order and stoichiometry of a reaction❌
n some reaction, a product formed acts as a catalyst. This phenomenon is called;
Autocatalysis
The reaction rate in forward direction decreases with the passage of time because:
Concentration of reactants decreases
For the reaction 2NO + O2 ➡2NO2, the rate equation for the forward reacton is:
Rate = k[NO]^2[O2]
Choose the type of catalysis in the following reaction:
2SO2 ➡2SO3
Homogenous catalysis
What is hte easure of activation energy in an endothermic reaction?
The energy of activation of backward reaction is less than that of forward reaction
If energy of activated complex is close to energy of reactatns, it means that the reaction is:
Fast
According to collison theory of bimolecular reactions in gas phase, minimum amount of energy required for an effective collsion is known as:
Energy of activation
If the energy of activation of a chemical reaction is very low, the rate of that chemical reacton is observed to be very high because?
Number of efficient or fruit collisions increase
The influence of temperature on reaction rate is predicted by
Arrhenius Equation
For which change of temperature, the rate of reaction become approximately double
10°C
It is experimentally found that catalyst is used to:
Lower the activaton energy
Role of a catalyst in a chemical reaction is to:
Increase the rate of reaction
Glucose is converted into ethanol by the enzyme present in the yeast.
Zymase
In zero order reaction, the rate is independent of:
Concentration of the reactant
2A + B ➡Product
If the reactant ‘B’ is in excess, the order of reaction with respect to ‘A’ in given rate law. Rate = k[A]2[B] is:
2nd Order Reaction
The rate constant ‘k’ is 0.693 min^-1/ The half life for the 1st order reaction will be:
1 min
Units of k in first order reaction is:
s^-1
Rate of first order reaction depends upon:
Concentration of one reactant
The unit of rate constatn is same as that of rate of reaction in:
Zero order reaction
Rate of photochemical reactions do not change with the change in concentrato of reactants, What is the order of such reactions?
Zero Order Reaction
The half-life of N2O5 at 45° is 24 minutes.How long will it take for sample of N2O5 to decay to 25% of its original concentration?
48 minute
When the change in concentration is 6 x 10^04 moldm^-3 and time for that change is 10 seconds, the rate of reaction will be:
6 x 10^-5 mol/dm^3 sec
For the first order reaction, half-life is related to the expression t1/2 = 0.693/k. Half lie is the :
Time taken for the concentration of the reactant to fall to half of its original value
The rate of reaction involving ions can be studied by method:
Electrical Conducitivity
If the reactants or product of a chemical reaction can absorb ultraviolet, visible or inra-red radiaton then the rate of a chemical reaction can be best be measured by which of the following methods?
Spectrometry
If concentration time graph of a reactant indicates a constant half-life, then the order reaction with respect the reactant is:
First Order
Choose the one which is not the assumption of collision theory of reaction rate.
For hdyrogen molecule for the formation from atoms require specific orientation
For exothermic reaction reversible reaction activation energy for forward direction depends upon:
➡Temperature
➡Nature of Product
What is the measure of activation energy is an endothermic reaction?
The energy of activation of backward reaction is less than that of forward reacton
What is the measure of activation energy is an endothermic reaction?
The energy of activation of backward reaction is less than that of forward reaction
The unit of rate constant is the same as that of the rate of raection in:
Zero order reaction
The study of rates of chemical reactions and the factors that affect the rates of chemical reactions is knwon as:
Chemical Kinetics
For a reaction
A(g) ➡Product
When the concentration of A doubles, the rate of reactions increased four folds, which means it is:
2nd Order Reaction
For which of the following order of reacton, rate of reacton is inversely proportional to the concentration reaction?
Negative Order of Reaction
For 1st order reacton, rate constant has units:
s^-1
For a reaction lke X +2Y ➡Z
Rate=k[X][Y]^2
If concentration of X and Y is tripled, then rate of reaction will increase:
27 times
The order of reaction cannot be determined by:
➡Optical Rotation Method✅
➡Differential❌
➡Graphical ❌
➡Half-Life Method❌
The rate of a chemical reaction doubles for every 10°C rise of temperature.If the temperature is raised by 70°C, the rate of reaction increases by about:
128
Half-Life of raioactive isotope is 60days. Days required when 12.5% concentration is left behind:
180
One of the following is a chemical method for determiation for rate of reaction:
Titrimetry
Half-Life of the reaction becomes half when initial concentration of reactants are doubled. The order of the reaction wll be:
Second Order
Slowest step in the reaction is called:
Rate determining step
In a reaction, A + B ➡Product, rate is doubled when the concentration fo B is doubled, and rate increase by a factor ffo 4 when the concentratons of both the reactants (A and B are doubled, rate law for the reaction can be written as)
Rate=k[A][B]
Which will hcange for first order reaction with time:
Rate of reaction
A certain reaction has the rate equation, Rate=k[A][B]^2. The rate is 2.5 x 10^-3 mol/dm^3 s. When [A] is 0.2mol/dm^3 and [B] is 0.050 mol/dm^3. Calculate the numerical value of rate constant.
5.0
Half-life of certain reaction decreases with decrease in concentration. Order of reaction is:
Zero Order
Rate of following reaction can be expressed as
PCl5 ➡PCl3 + Cl2
Rate = -d[PCl3]/dt
In the hydrolysis of an organic chloride in the presence of large excess of water:
Pseudo First Order
Which of the following statement is correct about zero order reaction:
➡All photochemical reactions are zero order
➡Rate is independent of concentration
➡Half-life is directly proportional to initial concentration
If during reaction, there is rotation in plane polarized light, then its rate can be determined by:
Optical Rotation method
The unit of rate constant ‘k’ is same as rate of reaction in:
Zero Order Reaction
The value of specific rate constant ‘k’ for first order reaction depends on the:
Temperature
What happens to rate of reaction if concentration of A and B are doubled? The rate expression of a reaction is, Rate=k[A][B]^2
Increased Eight Times
For the reaction A+B+C➡Product, Rate=k[A]^1/2[B]^1/3[C]1/4. The order of reaction is:
13/12
Which one is NOT physcial method or rate determination of chemical reaction:
➡Half-Life method✅
➡Dilatometric method❌
➡Spectrometric method❌
➡Optical Rotation method❌
During reaction,there is small cahnge in volume then the rate can be determined by:
Dilatometric Method
For third order reaction, rate constant ‘k’ has units:
mol^-2 dm^+6 s^-1
Which of the followings is pseudo first order reaction:
➡Acid catalyzed hydrolysis of an ester
➡Hydrolysis of tertiary butyl bromide
All are correct about zero order except:
➡All photochemical reactions are zero order❌
➡Radioactive decay follows zero order✅
➡Rate is independent of concentration❌
➡Half-life is directly proportional to initial concentration❌
In a reaction 2X +Y ➡M + N
If the concentration of Y kept constant and that of X is trippled. The rate of reaction will:
Increase 9 times
Photosynthesis, a photochemical reaction ahs order of reaction:
0
Concentration of reactants and products at the state of equilibirum may be:
➡Concentration (Reactant) = Concentration (Product)
➡Concentration (Reactant) > Concentration (Product)
➡Concentration (Reactant) < Concentration (Product)
The change in concentration of reactants or products
per unit time is called rate of reaction. The rate of
reaction:
Decreases as the reaction proceeds
With the increase of 10°C temperature, the rate of
reaction doubles. This increase in rate of reaction is due
to:
Increase in number of effective collision
The minimum amount of energy required for an
effective collision is called activation energy. Which one
of the following statements is incorrect about activation
energy?
Ea= Activation Energy
K= Specific Rate Constant
Ea is directly proportional to k
Order of reaction is the number of reacting molecules
whose concentration alters as a result of chemical
change. For which order of reaction, the unit of rate
constant (k) is the same as that of rate of reaction?
Zero order reaction
Which of the following statements about order of
reaction is incorrect?
➡It determines mechanism of reaction❌
➡It is determined experimentally❌
➡It is associated with rate equation❌
➡It is always equal to molecularity✅
In which of the following order of reaction, the half-life is independent of initial concentration?
1st Order
All of the following factors affect rate of reaction EXCEPT:
➡Concentration of reactants❌
➡Molecularity✅
➡Catalyst❌
➡Temperature❌
The addition of catalyst to a reaction can:
Change the activation energy
The experimental relationship between rate of reaction and concentration of reactant is called
Rate Law
The specific rate constant is equal to rate of reaction when concentration of reactants are taken as unity.Which of the following factors affects specific rate constant?
Temperature
A reaction in which catalyst is used is called catalysis. Which of the following is an example of heterogeneous catalysis?
2SO2 + O2 ➡2SO3
Half life cycle of an order of reaction is inversely
proportional to initial concentration raised to the power
one less than order of reaction. For which of the
following half-life of an order of reaction is inversely
proportional to the initial concentration of reactants?
2nd order
If the reaction P + Q ➡R + S is described as being of zero order w.r.t to P. It means that:
The rate of reaecton is independent of conc. of P
Which one of the following correctly represents the
units of the rate constant k for a first order reaction?
s^-1
If rate of reaction decay of a radioactive isotope
decreases from 200 counts per minutes to 25 counts per
minute after 24 hours. What is half life?
8 hours
Consider the general reaction nA ➡Product. The
rate of equation for a reaction is given by rate of
reaction = k [A]n If the value of n = 2. Then the unit of k for the 2nd order of reaction is:
mol^-1 dm^3 s^-1
For a gaseous reaction 2X + Y ➡X
Rate= k[X]^2[Y]^0
If the pressure in the reaction vessel is doubled but temperature remains constant. By what factor does the rate of reaction increases?
4
A radioactive element has two isotopes, “G ” and “H ”,
with half lives of 5 min and 15 min respectively. An
experiment starts with 4 times as many atoms of “G ” as
of “H ”. Radioactive decay is a first order reaction. How
long will it be before the number of atoms of “G ” left
equal the number of atoms of “H ” left?
15 mn
All of the following are characteristic features of
catalyst EXCEPT:
➡It speeds up a chemical reaction❌
➡It is used in smaller amount❌
➡It can intiate a chemical reaction❌
➡Enthalpy change of a catalyzed and uncatalyzed reaction is not same✅
In some of the reactions, a product formed acts as a catalyst, this phenomenon is called:
Autocatalysis
Identify the incorrect statement about enzyme catalysis:
➡It is highly specific in action❌
➡Its activity is increased by the presence of activator❌
➡It shows maximum rate of reaction at minimum
temperature✅
➡Its catalytic activity is inhibited by a poison❌
A solution A of concentraton 0.10 mol dm^-3 undergoes first order reacton at an initial rate of 5.0 x 10^-4 mol dm^-3 s^-1. The value of rate constant for this reaction is:
5 x 10^-3 s^-1
Which of the following is an example of first order
reaction?
2N2O5 ➡2N2O4 + O2
The reaction which takes place among the molecules
when they have:
➡Activation energy
➡Proper Orinetation
Choose the type of cataylsis in the following reaction:
2SO2 + O2 ➡2SO3
Homogenous Catalyst
(➡If NO is used then it is homogenous catalyst
➡If V2O5 us used the it is heterogenous catalyst)
Which of the following physical methods is used to
determine rate of reaction when rate of reaction depends
on the rate of change in the concentration of reacting ions
or ions are formed during the reaction?
Electrical Conductivity Method
The rate law for the reacton is rate=k[A][B]^2/3. The order of eration s:
5/3
The half-life of followign first order reaction A➡B+C is 10min. The concentraton of A would be reduced to 12.5% of original concentration in:
30 min
In the given reacton 2A + B➡Products, it is observed on quadrupling the conc. of B, rate of reaction jcnreases 16 times. The order of reacton with respect to B is:
2
If rate cosntant for any reaction is equal to rate o freaction at all concentrations. Then the order of reacton will be:
Zero
The rate of chemical reaction roguhyl doubles for every 10°C rise of temperature. If temperature is raised by 20°C, the rate may become:
4 times
In Rate=k[A][B], the second order reaction become ___ if [A] is i alrge excess:
Pseudo First Order
In a reaction, A + B ➡C, if concentration of A and B is doubled, then rate of reaction will increase:
8 times
Half-life of 1st order reaction A➡B is 0.693/2 seconds, its rate constant is:
2s^-1
Rate of first order reaction depends on:
Concentration of one reactant
For which order of reaction rate constant has same units as rate of reaction:
Zero Order Reacton
The rate expression of a reaction is, Rate = k[A][B]2. What happens to rate of reaction if concentrations of A and B are doubled?
Increased eight times
The units of second order rate constant are usually expressed as:
mol^-1 dm^3 s^-1
Those substances which slow down a reaction are called:
Inhibtors
Decomposition o formic acid into CO2 and H2 is catalyzed by:
Cu
If T2 > T1 which is ncorrect for a eraction:
A + heat ➡B
All molecules have energy greater than Ea
How much rise in temperature approximately doubles the reaction rate?
10K
log K = log A ^-Ea/2.303RT, considering above equation which is incorrect:
➡K α T
➡Value of A s independent of reactants are products
➡K α 1/Ea
➡K α Ea
Generally increase in temperature results in:
Increase the rate of any reacton whether the reaction is an endothermic and exothermic
Which have moderate speed?
Molecular Reactions
In concentration time graph steepness of the graph indicates, rate of the reacton has ___ relatioship with steepness:
Direct
Which is incorrect for order for reaction:
Order of reaction and molecularity both are always the same
Those substances which make a catalyst more effective?
➡Catalyst for a catalyst
➡Promotor
For a radioactive substance, half-life perod of a first order reaction is independent of:
Initial concentration of the reactant
All kind of volumetric anaylsis methods are considered as __ methods to study the reaction rate.
Chemical
The energy of activation of forward reaction is less than that of backward reaction in:
Exothermic Reaction
A catalyst:
Increases the rate of forward reaction
Poisoning of a catalyst may be temporary or permanent, in permanent posioning:
Physical state of catalyst changes
When rate of reacton is retarded by adding a substance, it is said to be:
Negative Catalyst
Indicate the enzyme which catalyzes the followign reaction?
(NH2)2CO + H2O ➡2NH3 + CO2
Urease
Indicate the enzyme which catalyzes the followign reaction?
(NH2)2CO + H2O ➡2NH3 + CO2
Urease
When a reaction proceeds in a sequence of steps, the overall rate is determined by:
Slowest step
2NO2 ➡NO2 + O2 is order of reaction:
Rate α [NO2]2
Second
Rate of reaction depends upon:
➡Temperature
➡Pressure
➡Concentraton
The protein part of an enzyme is called:
Apoenzyme
With the increase in temperature, the efficiency of a catalyst:
Increases to maximum and then decreases
A process is said to be a homogenous catalysis when:
Reactants, Products and Catalyst all are in same phase
When concentraton of reactants is doubled then half-life period of first order reaction:
Does not change
Activation energy is the gap between energy states of:
➡Reactants
➡Activated Complex
Radioactive disintegration are usually:
First Order
The energy of activation always have ___ relationship with the reaction rate
Inverse
The unit of slope of the straight line obtained by plotting a graph between 1/T on x-axix and log K on y-axis, is:
K
In optical rotation method the angle through which plane polarized light is rotated by the reaction mixture is measured by a:
Polarimeter
The half-life of second order reacton is equal to:
1/Ka
Which statement is incorrect?
At the end of interval the average rate becomes lower than the average rate
Which is the correct relation between the half-life and third order reaction:
[t1/2] x 1/a^2
If reaction rate increases four times on doubling the initial concentration of reactants then the reaction is:
Second Order
The disintegration of radoactive Uranium-235 is a:
First Order Reaction
Formic acid is decomposed into CO and H2O in the presence of:
Al2O3
Which one of the reaction proceed at moderate rate?
Hydrolysis of an ester
