Liquid Solution

Question 1

Define Vapour pressure.

Answer 1

Vapour pressure is the pressure exerted by the vapours of a liquid which are in equilibrium with it at a given temperature. It’s not a surface phenomenon. It increase with increase in temperature.

Question 2

Relative lowering of vapour pressure.

Answer 2

P’-P/P’= X(Solute)

= i.n(solute)/(i.n(solute)+n(solvent))

Question 3

What are ideal solution?

Answer 3

Solutions which obey roults law are ideal solution. 
Delta H(mix)=0
Delta V(mix)=0
Delta S(mix)>0
Delta G(mix)

Question 4

What can you say about non ideal solution with a positive deviation?

Answer 4

Delta H(mix) = +ve 
Delta V(mix) = +ve 
Delta S(mix) = +ve 
Delta G(mix) = -ve

Eg- Water + Methanol / Ethanol

Question 5

What can you say about non ideal solution with a negative deviation ?

Answer 5

Delta H(mix) = -ve 
Delta V(mix) = -ve
Delta S(mix) = +ve 
Delta G(mix) = -ve

Eg- Water + Ethanoic Acid / Nitric Acid.

Question 6

What are Azeotropes ?

Answer 6

Azeotropes are binary mixtures having the same composition in liquid and vapour phase and boil at a constant temperature.

Question 7

Which type of solution form minimum boiling Azeotropes at a specific composition ?

Answer 7

The solution which show a large positive deviation from roults law form minimum boiling Azeotropes at a specific composition.

Question 8

Which type of solution form maximum boiling Azeotropes at a specific composition?

Answer 8

The solutions which show a large negative deviation from roults law form maximum boiling Azeotropes at a specific composition.

Question 9

What is osmotic pressure ?

Answer 9

Osmotic pressure is the pressure which must be applied to the concentrated solution in order to stope osmosis.

Question 10

On basis of osmotic pressure , what are the different type of solution that can be classified ?

Answer 10

Isotonic solution- Two solutions having same osmotic pressure.
Hypertonic solution - solution with higher osmotic pressure among the two
Hypotonic solution - solution with lower osmotic pressure among the two.

Question 11

Elevation in boiling point

Answer 11

T(b)=i.K(b)m

Question 12

Depression in freezing point

Answer 12

T(f)=i.K(f)m

Question 13

What is the formula for osmotic pressure?

Answer 13

Pi = i. CRT

Question 14

Vapour density of a gas VD=?

Answer 14

VD= M/2

Question 15

Molality in terms of m1, w1 and w2

Answer 15

m= 1000 w1 / m1w2
; w1 = mass of solute
w2= mass of solvent
m1= molar mass of solute

Question 16

Henry’s Law p=?

Answer 16

p=K X
; p= partial pressure of gas above solution
K= Henry law constant
X= mole fraction of gas in solution

Question 17

Effect of temperature on solubility of gas ln C2/C1=?

Answer 17

ln C2/C1= ΔH/R (1/T1- 1/T2)
; ΔH= Heat of solution of 1 mole of gas
C1,C2= conc of gas at that temp

Question 18

Normality B in terms of w1 , E1 and V =?

Answer 18

N= 1000 w1/E1 V

Question 19

Volume per cent in terms of w1 and V =?

Answer 19

C= 100 w1/ V

Question 20

Volume per litre C=?

Answer 20

C= 1000 w1 / V

Question 21

Millimoles =?

Answer 21

MV = millimoles ( say x) = x/1000 moles

Question 22

Normality =?

Answer 22

Normality = nfactor x Molarity