Question 301 markMCQSection B

Which one of the following are the correct observations about acetic acid ?

Carbon and its Compounds
Properties of Carbon Compounds

Options

(A)It turns blue litmus red and smells like vinegar
(B)It turns blue litmus red and smells like burning sulphur
(C)It turns red litmus blue and smells like vinegar
(D)It turns red litmus blue and has a fruity smell

Official answer

Option A is correct. Acetic acid (CH3COOHCH_3COOH) is acidic in nature, which causes it to turn blue litmus paper red, and it possesses a characteristic sharp, sour smell of vinegar.

Answer keywords:acetic acidblue litmus redvinegar smellcarboxylic acidCH3COOHCH_3COOH

Marking scheme

  1. 1.1 mark for selecting the correct option (A).

Hint

Think about the chemical nature of carboxylic acids like acetic acid (CH3COOHCH_3COOH) on indicators, and recall what common household condiment is made from dilute acetic acid.

Quick oral answer

Acetic acid turns blue litmus paper red because it is acidic. It has a characteristic vinegar smell because vinegar itself is a dilute solution of acetic acid in water.

Common mistakes

  1. 1.Confusing acetic acid with a base and selecting options that mention turning red litmus blue.
  2. 2.Confusing the pungent vinegar smell of acetic acid with the sweet, fruity smell of esters.

Analysis and explanation

  • Why A is correct: Acetic acid (CH3COOHCH_3COOH) belongs to the carboxylic acid group (as shown in Table 4.3 of the text). Being an acid, it dissociates in water to release hydrogen ions, which turns blue litmus paper red. Additionally, dilute acetic acid is the primary constituent of vinegar, giving it its characteristic vinegar-like smell.
  • Why B is incorrect: The smell of burning sulphur is characteristic of sulphur dioxide (SO2SO_2), which is highly suffocating and choking, unlike the sour smell of acetic acid.
  • Why C is incorrect: Acids turn blue litmus red. Turning red litmus blue is a characteristic property of basic substances, not acidic ones like acetic acid.
  • Why D is incorrect: Acetic acid does not turn red litmus blue. Furthermore, a sweet, fruity smell is characteristic of esters, whereas acetic acid has a sharp, pungent vinegar smell.

Interesting facts

A 5−8%5-8\% solution of acetic acid in water is called vinegar and is widely used as a preservative in pickles and salad dressings.

Question details

Q30 of 41 questions

Board
CBSE
Class
Class 10
Subject
Science
Year
2012
Section
Section B
Marks
1
Type
MCQ
Chapter
Carbon and its Compounds
Topic
Properties of Carbon Compounds
Bloom's level
Remembering
Syllabus topic
Properties of ethanoic acid (acetic acid)

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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 Carbon Compounds" 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.