Question

A student takes about 2 ml ethanoic acid in a dry test tube and adds a pinch of sodium hydrogen carbonate to it. He reports the following observations : I. Immediately a colourless and odorless gas evolves with a brisk effervescence. II. The gas turns lime water milky when passed through it. III. The gas burns with an explosion when a burning splinter is brought near it‘ IV. The gas extinguishes the burning splinter that is brought near it. The correct observations are : (A) 1, II and III (B) It, 111 and IV (C) III, IV and I (D) I, II and IV

Answer 1

c.

it is the answer for your question.

Answer 2

Dear Student,

◆ Answer -

(D) I, II and IV

● Explaination -

Ethanoic acid on reaction with sodium hydrogen carbonate gives sodium ethanoate with CO2 as byproduct.

CH3COOH + NaHCO3 --> CH3COONa + H2O + CO2

CO2 gas evolved is colourless gas observed with brisk effervescence.

When CO2 is passed through lime water, white precipitate of calcium carbonate is formed that makes limewater cloudy in appearance.

Ca(OH)2 + CO2 --> CaCO3 + H2O

As CO2 doesn't support combustion, it is used in fire extinguishers.

Hence, option (D) i.e. I, II and IV are true.

Best luck...