Question

Write the effect of dilute hydrochloric acid on the colour of each one of the following indicators?

(i) Methyl orange

Answer 1

1. Indicators

Indicators are substances that produce a distinct and observable change as per the solution's nature. For example, indicators are used to distinguish between acidic and basic solutions. Some examples are Litmus, red cabbage, phenolphthalein, etc.

2. Effect on Methyl orange

Methyl orange is an acid-base indicator.

1. When methyl orange is placed in acidic solutions, the colour of the solution changes to red.
2. When methyl orange is placed in basic solutions, the colour of the solution changes to yellow.

The given solution is dilute HCl (Hydrochloric acid). Since HCl is a strong acid, its solution will have an acidic nature. So, a change in red colour will be observed.

Thus, the addition of dilute hydrochloric acid will cause a red colour in methyl orange.