Abnormal Value of Molar Mass NEET Questions

Abnormal Value of Molar Mass MCQ Questions

13.
Which of the following is the van't Hoff factor–modified expression for osmotic pressure of a solution?
A.
π = iCRT
B.
π = CRT/i
C.
π = CRT
D.
π = i²CRT
ANSWER :
A. π = iCRT
14.
What is the correct van't Hoff factor–modified formula for the depression in freezing point of a solution?
A.
ΔTf = i × Kf × m
B.
ΔTf = Kf × m
C.
ΔTf = Kf / (i × m)
D.
ΔTf = Kf × m / i
ANSWER :
A. ΔTf = i × Kf × m
15.
Acetic acid dimerizes to a significant extent when dissolved in benzene. What effect does this have on its observed molar mass compared to its normal molar mass?
A.
Observed molar mass becomes lower than normal molar mass
B.
Observed molar mass becomes approximately double the normal molar mass
C.
Observed molar mass remains equal to normal molar mass
D.
Observed molar mass becomes zero
ANSWER :
B. Observed molar mass becomes approximately double the normal molar mass
16.
For an electrolyte that dissociates into 'n' ions per formula unit with degree of dissociation α, which expression correctly gives the van't Hoff factor?
A.
i = 1 + α(n − 1)
B.
i = 1 − α(n − 1)
C.
i = nα
D.
i = 1/(1 + α(n−1))
ANSWER :
A. i = 1 + α(n − 1)
17.
For a solute undergoing association where 'n' molecules combine to form one associated species with degree of association α, which expression correctly gives the van't Hoff factor?
A.
i = 1 − α(1 − 1/n)
B.
i = 1 + α(1 − 1/n)
C.
i = nα
D.
i = 1/n
ANSWER :
A. i = 1 − α(1 − 1/n)
18.
If the observed molar mass of a solute is found to be lower than its calculated (normal) molar mass, what does this indicate about the solute's behaviour in solution?
A.
The solute is associating in solution
B.
The solute has no effect on colligative properties
C.
The solute is completely insoluble
D.
The solute is dissociating in solution
ANSWER :
D. The solute is dissociating in solution