Question 341 markMCQSection B

When solid sodium bicarbonate is added to a dilute aqueous solution of ethanoic acid

Carbon and its Compounds
Chemical Properties of Carbon Compounds

Options

(A)Brisk effervescence takes place and an odourless gas is evolved.
(B)Brisk effervescence takes place and a pungent smelling gas is evolved.
(C)No effervescence occurs and no gas is evolved.
(D)Brisk effervescence occurs and a gas is evolved which helps a glowing splinter to burn with a flame.

Official answer

Brisk effervescence takes place and an odourless gas is evolved.

Answer keywords:brisk effervescenceodourless gascarbon dioxideCO2sodium bicarbonate

Marking scheme

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

Hint

Recall the reaction between an acid and a metal hydrogen-carbonate mentioned in the text context of carbon forms.

Quick oral answer

The gas evolved is carbon dioxide (CO2CO_2). It can be tested by passing it through lime water, which turns milky.

Common mistakes

  1. 1.Identifying the gas as oxygen which supports combustion.
  2. 2.Confusing the odourless CO2 with pungent gases like SO2 or NH3.

Analysis and explanation

When ethanoic acid (acetic acid, CH3COOHCH_3COOH) reacts with sodium bicarbonate (NaHCO3NaHCO_3), a neutralization reaction occurs that releases carbon dioxide gas (CO2CO_2). The reaction is: CH3COOH+NaHCO3→CH3COONa+H2O+CO2↑CH_3COOH + NaHCO_3 \rightarrow CH_3COONa + H_2O + CO_2 \uparrow. The rapid evolution of CO2CO_2 causes 'brisk effervescence'. Carbon dioxide is a colourless and odourless gas, making Option A correct. Option B is wrong because CO2CO_2 is not pungent. Option C is wrong because a reaction definitely occurs. Option D is wrong because CO2CO_2 does not support combustion; it would actually extinguish a glowing splinter.

Interesting facts

This reaction is the basis for the 'volcano' experiment often performed in school science fairs.

Question details

Q34 of 41 questions

Board
CBSE
Class
Class 10
Subject
Science
Year
2011
Section
Section B
Marks
1
Type
MCQ
Chapter
Carbon and its Compounds
Topic
Chemical Properties of Carbon Compounds
Bloom's level
Applying
Syllabus topic
Reactions of Ethanoic Acid

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Frequently asked questions

How many marks does this question carry in CBSE Class 10 Science 2011?

This question carries 1 mark in the CBSE Class 10 Science 2011 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 "Chemical Properties of Carbon Compounds" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2011 paper?

This is a MCQ question from Section B in the CBSE Class 10 Science 2011 paper.