The Change in Colour of the Moist Litmus Paper in the Given Set Up is Due to

The change in colour of the moist litmus paper in the given set up is due to

i. presence of acid
ii. presence of base
iii. presence of H⁺(aq) in the solution
iv. presence of Litmus which acts as an indicator

(a) i and ii
(b) Only ii
(c) Only iii
(d) Only iv.

Correct answer is option C. Only iii. Explanation: The change in colour of the moist litmus paper in the given set up is due to presence of H⁺(aq) in the solution.