On adding acetic acid to sodium hydrogen carbonate in a test tube, a student observes
On adding acetic acid to sodium hydrogen carbonate in a test tube, a student observes
Options
When acetic acid () is added to sodium hydrogen carbonate (), an acid-base reaction occurs, producing sodium acetate, water, and carbon dioxide gas (). The evolution of carbon dioxide gas is observed as brisk effervescence (bubbles of a colourless and odourless gas).
Marking Scheme
- 1Identification of correct option C. (1 mark)
Hint
Recall the general reaction: . What does carbon dioxide look and smell like?
Quick Oral Answer
We observe brisk effervescence due to the evolution of carbon dioxide gas, which is colourless and odourless.
Analysis & Explanation
The reaction between a carboxylic acid (acetic acid) and a metal hydrogen carbonate (sodium hydrogen carbonate) always yields a salt, water, and carbon dioxide gas.
- Option C is correct because gas is evolved with brisk effervescence, which appears as bubbles of a colourless and odourless gas.
- Option A is incorrect because a rapid chemical reaction does take place.
- Option B is incorrect because is odourless, not pungent.
- Option D is incorrect because although acetic acid itself smells like vinegar, the primary immediate observation of the active reaction is the vigorous bubbling of the evolved gas.
Common Mistakes
- 1Confusing the smell of the reactant (acetic acid has a vinegar smell) with the observation of the gas evolved (carbon dioxide is odourless).
Interesting Facts
This reaction is the classic chemical basis behind school science 'volcano' experiments, where the rapid release of gas creates foaming bubbles.
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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.