Waec Model Questions Vol1 2020 Chemistry Question 21

Practice objective / multiple choice question 21 from the 2020 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2020 Chemistry Objective / Multiple Choice Hard Difficulty
Question 21 WAEC_MODEL_QUESTIONS_VOL1 • 2020 • CHEMISTRY • objective

A 12.0 g sample of pure malonic acid (HOOC‑CH2‑COOH, molar mass 118.09 g·mol⁻¹) is esterified with excess ethanol in the presence of concentrated H₂SO₄ according to: HOOC‑CH₂‑COOH + 2 C₂H₅OH → CH₃CH₂OOC‑CH₂‑COOCH₂CH₃ + 2 H₂O. If the reaction gives 78% isolated yield of diethyl malonate, calculate (a) the mass of diethyl malonate obtained and (b) the percent by mass of water formed relative to the original malonic acid sample.

Answer Options

A. a) 14.6 g of diethyl malonate; b) 26.3 % water by mass
Correct Answer B. a) 13.8 g of diethyl malonate; b) 23.8 % water by mass
C. a) 11.9 g of diethyl malonate; b) 19.7 % water by mass
D. a) 12.5 g of diethyl malonate; b) 21.5 % water by mass
Correct Answer
B
Correct Option:
a) 13.8 g of diethyl malonate; b) 23.8 % water by mass

About This Question

This is Waec Model Questions Vol1 2020 Chemistry Question 21. It is a objective / multiple choice question from the 2020 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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