Abnormal Value of Molar Mass NEET Questions

Physical Chemistry - Solutions

Abnormal Value of Molar Mass MCQ Questions


7.
Benzoic acid dimerizes almost completely when dissolved in benzene due to hydrogen bonding. What would be the approximate van't Hoff factor (i) for this system?
A.
i ≈ 2
B.
i ≈ 1
C.
i ≈ 0.5
D.
i ≈ 3
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ANSWER :
C. i ≈ 0.5
8.
When sodium chloride (NaCl) is completely dissociated in water, what is the theoretical value of its van't Hoff factor (i)?
A.
i = 1
B.
i = 2
C.
i = 3
D.
i = 4
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ANSWER :
B. i = 2
9.
For a strong electrolyte such as K3[Fe(CN)6], which dissociates completely into 4 ions in solution, what is the theoretical van't Hoff factor (i)?
A.
i = 2
B.
i = 3
C.
i = 4
D.
i = 1
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ANSWER :
C. i = 4
10.
For CaCl2, which dissociates completely in aqueous solution, what is the expected theoretical value of the van't Hoff factor (i)?
A.
i = 1
B.
i = 2
C.
i = 3
D.
i = 4
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ANSWER :
C. i = 3
11.
When the van't Hoff factor (i) is used to modify colligative property expressions, which of the following relations correctly represents the modified relative lowering of vapour pressure?
A.
(p° − p)/p° = i × (n2/n1)
B.
(p° − p)/p° = (n2/n1)/i
C.
(p° − p)/p° = n2/n1 (unaffected by i)
D.
(p° − p)/p° = i²(n2/n1)
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ANSWER :
A. (p° − p)/p° = i × (n2/n1)
12.
Which of the following is the van't Hoff factor–modified expression for the elevation in boiling point of a solution?
A.
ΔTb = Kb × m
B.
ΔTb = i × Kb × m
C.
ΔTb = Kb × m / i
D.
ΔTb = Kb / (i × m)
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ANSWER :
B. ΔTb = i × Kb × m