Q28
1 markMCQSection B

On adding 2 mL acetic acid to 2 mL of water in a test tube, it was observed that

Carbon and its Compounds
Properties of Ethanoic Acid

Options

(A)a clear and transparent solution is formed
(B)a white precipitate is formed almost immediately
(C)two separate layers were formed
(D)a colourless and odourless gas is evolved
Official Answer

When acetic acid (CH3COOHCH_3COOH) is added to water, it dissolves completely in all proportions to form a clear, homogeneous, and transparent solution. No chemical reaction occurs that would produce a precipitate or evolve a gas, and no phase separation occurs because acetic acid is highly miscible with water.

Acetic acidmiscibleclear and transparent solutionhomogeneous

Marking Scheme

  • 1Identification of correct option A. (1 mark)

Hint

Think about vinegar, which is a dilute solution of acetic acid in water. Is vinegar cloudy, layered, or clear?

Quick Oral Answer

A clear and transparent solution is formed because acetic acid is completely miscible with water due to hydrogen bonding.

Analysis & Explanation

Acetic acid (CH3COOHCH_3COOH) contains a polar carboxylic acid group (−COOH-COOH) which readily forms hydrogen bonds with water molecules. Because of this strong intermolecular hydrogen bonding, acetic acid is completely miscible with water.

  • Option A is correct because a clear, homogeneous, and transparent solution is formed.
  • Option B is incorrect because no precipitate is formed.
  • Option C is incorrect because acetic acid does not separate into layers like hydrophobic substances (e.g., oil) do.
  • Option D is incorrect because mixing acetic acid with water is a physical dissolution process, not a chemical reaction that evolves gas.

Common Mistakes

  1. 1Confusing the physical dissolution of acetic acid in water with its chemical reaction with sodium bicarbonate (which does evolve a gas).

Interesting Facts

A 5%5\% to 8%8\% solution of acetic acid in water is commonly known as vinegar, which is widely used as a food preservative.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2012?

This question carries 1 mark in the CBSE Class 10 Science 2012 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Carbon and its Compounds" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Properties of Ethanoic Acid" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2012 paper?

This is a MCQ question from Section B in the CBSE Class 10 Science 2012 paper.