Write the effect of dilute hydrochloric acid on the colour of the following indicators:
Blue litmus

Explanation

**Step-by-Step Solution:**

1. **Understanding Litmus Indicators**: Litmus is a natural pH indicator that comes in two colors: red and blue. Red litmus paper turns blue in the presence of a base, while blue litmus paper turns red in the presence of an acid.

2. **Identifying the Nature of Hydrochloric Acid**: Hydrochloric acid (HCl) is a strong acid. When it is dilute, it still retains its acidic properties, which means it has a pH of less than 7.

3. **Effect of Dilute Hydrochloric Acid on Blue Litmus**: When blue litmus paper is exposed to an acidic solution (like dilute hydrochloric acid), it will undergo a color change. Specifically, blue litmus paper will turn red in the presence of an acid.

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