Molecules of benzoic acid (C6H5COOH) dimerize in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimer in the solution is 80, then w is (Given that Kf = 5 K kg mol−1, Molar mass of benzoic acid = 122 g mol−1)
(a)
1.8g
(b)
2.4g
(c)
1.0g
(d)
1.5g
(a)
1.8g
(b)
2.4g
(c)
1.0g
(d)
1.5g
Question ID - 52396 | SaraNextGen Top Answer Molecules of benzoic acid (C6H5COOH) dimerize in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimer in the solution is 80, then w is (Given that Kf = 5 K kg mol−1, Molar mass of benzoic acid = 122 g mol−1)
(a)
1.8g
(b)
2.4g
(c)
1.0g
(d)
1.5g
Molecules of benzoic acid (C6H5COOH) dimerize in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimer in the solution is 80, then w is (Given that Kf = 5 K kg mol−1, Molar mass of benzoic acid = 122 g mol−1)
|
(a) |
1.8g |
(b) |
2.4g |
|
(c) |
1.0g |
(d) |
1.5g |
1 Answer
127 votes
Answer Key / Explanation : (b) -
f T = i kf m
2=0.6 × 5 × 
(i = 1 − 0.8 +0.4 = 0.6)
W=2.44g
127 votes
Answer Link
127