A student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from 9.3 g of aniline. However, the student has managed to obtain 11 g of dry acetanilide. The % yield of this reaction is :-
Q. A student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from 9.3 g of aniline. However, the student has managed to obtain 11 g of dry acetanilide. The % yield of this reaction is :-

(A) 59.5%

(B) 72.5%

(C) 97.5%

(D) 81.5%

Correct Answer: 81.5%

Explanation

Aniline reacts with acetic anhydride to form acetanilide in a 1 : 1 molar ratio.

Molar mass of aniline = 93 g mol⁻¹

Moles of aniline taken:

9.3 / 93 = 0.1 mol

Molar mass of acetanilide = 135 g mol⁻¹

Theoretical yield of acetanilide:

0.1 × 135 = 13.5 g

Actual yield of acetanilide obtained = 11 g

Percentage yield is given by:

(Actual yield / Theoretical yield) × 100

= (11 / 13.5) × 100

= 81.5%

Hence, the percentage yield of the reaction is 81.5%.

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