Change set

Pick exam & year, then Go.

Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q52 (CDS-II/2023) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry Answer Verified

During white-washing of walls, slaked lime reacts slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Which of the following reactions represents this correctly?

Result
Your answer: —  ·  Correct: D
Explanation

During the process of white-washing, a solution of slaked lime (calcium hydroxide) is applied to the walls. This calcium hydroxide reacts slowly with the carbon dioxide present in the air to form a thin, shiny layer of calcium carbonate. The chemical reaction is represented as Ca(OH)₂ (aq) + CO₂ (g) ⟶ CaCO₃ (s) + H₂O (l). In this reaction, calcium hydroxide is in an aqueous state (aq) as it is applied as a solution, carbon dioxide is a gas (g), and the resulting calcium carbonate is a solid (s) precipitate that provides the white finish, while water is released as a liquid (l). This reaction is also the basis for the lime water test, where the formation of insoluble calcium carbonate turns the solution milky [2].

Sources

  1. [2] Science-Class VII . NCERT(Revised ed 2025) > Chapter 5: Changes Around Us: Physical and Chemical > Fig. 5.2: Blowing air in (a) tap water; (b) lime water > p. 61
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
72%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CDS-I · 2021 · Q92 Relevance score: 3.79

Calcium oxide reacts vigorously with water to produce slaked lime whose solution is used for white-washing walls. This slaked lime reacts with component (A) in air to form a thin layer of component (B) to give a shiny finish. What are the components (A) and (B) ?

CAPF · 2022 · Q39 Relevance score: -2.22

Calcium oxide reacts with water to produce slaked lime. It is an example of

CDS-II · 2014 · Q25 Relevance score: -2.49

When carbon dioxide is passed through lime water, the solution turns milky, but, on prolonged passage, the solution turns clear. This is because

NDA-I · 2021 · Q77 Relevance score: -3.63

Reaction of ick lime (CaO) with water to produce slaked lime (Ca(OH)2) is an example of