CBSE Class 10 Science
Question 48 of 60
Solved 2022 Term 1 Question Paper CBSE Class 10 Science — Question 24
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Question Question 48
50.0 mL of tap water was taken in a beaker. Hydrochloric acid was added drop by drop to water. The temperature and pH of the solution was noted. The following graph was obtained. Choose the correct statements related to this activity.

(i) The process of dissolving an acid in water is highly endothermic.
(ii) The pH of the solution increases rapidly on addition of acid.
(iii) The pH of the solution decreases rapidly on addition of acid.
(iv) The pH of tap water was around 7.0.
- (i) and (ii)
- (i) and (iii)
- (iii) and (iv)
- (ii) and (iv)
(iii) and (iv)
Reason — The pH of tap water was around 7.0 because tap water is a neutral solution. On addition of acid to water the heat energy is released hence the reaction is exothermic. The pH of the solution decreases rapidly from 3 to 1 with the addition of acid.