9.3 g of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is 100% completed is 10-1 g. (Given molar mass in g mol-1 N : 14, O : 16, C : 12, H : 1)
Answer
135
Solution
Acetylation of aniline (1 mol gives 1 mol):
[figure]
M(aniline, C6H7N) = 93 g mol-1; M(acetanilide, C8H9NO) = 135 g mol-1
n(aniline) = 9.393 = 0.1 mol = n(acetanilide)
∴ Mass = 0.1 × 135 = 13.5 g = 135 × 10-1 g
Answer: 135