Question Paper
Class / Subject: Class 7 (CBSE) · Science
Chapter: Chapter 2 — Chapter 2: Exploring Substances: Acidic, Basic, and Neutral
Time Allowed: 15 minutes
Max Marks: 6
1. An acid turns blue litmus paper: [1]
(A) red
(B) blue
(C) green
(D) colourless
2. A substance with a pH of 7 is: [1]
(A) neutral
(B) strongly acidic
(C) strongly basic
(D) undefined
3. Turmeric is used as a natural indicator because it turns: [1]
(A) reddish-brown in bases
(B) blue in acids
(C) green in acids
(D) black in bases
4. The reaction between an acid and a base is called: [1]
(A) neutralisation
(B) combustion
(C) oxidation
(D) evaporation
5. The general pattern of a neutralisation reaction is: [1]
(A) Acid + Base → Salt + Water
(B) Acid + Acid → Base
(C) Base + Base → Acid
(D) Salt + Water → Acid
6. Farmers add lime to soil to: [1]
(A) neutralise excess acidity
(B) increase acidity
(C) add colour
(D) add water only