Solutions Test

Result

Solutions Test - 3

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

A mixture of carbon monoxide and carbon dioxide is found to have a density of 1.7 g/lit. at S.T.P. The mole fraction of carbon monoxide is

A
0.37

B
44.1

C
0.30

D
0.50

Solution

At STP, 1 mol of any gas is 22.4 L.

Let moles of CO be X

Let moles of CO₂ be Y

Volume of solution = (X + Y)22.4 L

Mass of solution = 28X + 44Y

Hence, density = (28X + 44Y) / ((X+Y) 22.4) = 1.7

28X + 44Y = 38.08X + 38.08Y

10.08X = 5.92Y

hence, 1.703X = Y.

mole fraction of CO = X / (X + Y) = X / (X + 1.703X) = 1 / 2.703 = 0.37
Question 2
1 / -0

Which of the following is correct for a non-ideal solution of liquids A and B, showing positive deviation?

A
∆H_mix = –ve

B
∆V_mix = –ve

C
∆S_mix = +ve

D
All are correct

Solution

For solutions showing positive deviation. The intermolecular forces between solute are lower than that of ideal solution.

Its volume is higher than that of ideal solution due to positive deviation.

As lesser bonds are formed energy is absorbed as compared to ideal solution, this result in positive enthalpy change.

Entropy of system always increase due to increase in number of particles.

Therefore, ∆H_mix = +ve , ∆V_mix = +ve , ∆S_mix = +ve
Question 3
1 / -0

Which of these aqueous solution has the lowest boiling point?

A
0.15 M HCl

B
0.15 M CaCl₂ solution

C
0.4 M glucose solution

D
0.15 M urea solution

Solution

Van’t Hoff factor for HCl is 2 because it dissociates into H⁺ and Cl^-.

Van’t Hoff factor for CaCl₂ is 3 because it dissociate into Ca²⁺ and 2 Cl^-.

Van’t Hoff factor for glucose is 1 because it don’t dissociate.

Van’t Hoff factor factor for urea is 1 because it doesn’t dissociate.

Effective concentration of compound is = i x m where i is van’t Hoff factor and m is concentration.

Effective concentration for:

HCl = 0.15 x 2 = 0.3M

CaCl₂ = 0.15 x 3 = 0.45M

Glucose = 0.4M

Urea = 0.15M

As elevation in boiling point is proportional to effective concentration.

Therefore, urea solution has lowest boiling point.