Question

The indicator which produces a pink colour in an alkaline solution is ______.

Options

• methyl orange

• turmeric paper

• phenolphthalein

• litmus paper

Answer 1

The indicator which produces a pink colour in an alkaline solution is phenolphthalein.

Explanation:

Phenolphthalein is a synthetic chemical indicator that is highly sensitive to changes in pH levels. In neutral or acidic environments, the compound remains completely colourless. However, when introduced to an alkaline (basic) solution with a pH rising above 8.2, its molecular structure alters, causing it to produce a vivid pink colour. Conversely, methyl orange turns yellow, turmeric paper turns reddish-brown, and litmus paper turns blue in basic media.