Question

When a few drops of methyl orange indicator are added to sodium hydroxide solution, the colour acquired by it is :

• A. No specific colour
• B. yellow
• C. pink
• D. red

Answer 1

The correct option is B

yellow

1. Methyl orange is an indicator that is an orange colour dye and maintains its colour in a neutral medium.
2. In the acidic medium, the colour of the indicator becomes red and in the basic medium, the colour of the indicator becomes yellow.

Now if we see the dissociation reaction of Sodium hydroxide (NaOH),

$\mathrm{NaOH}\left(\mathrm{aq}\right)\stackrel{}{\to }{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$

1. Here Sodium hydroxide (NaOH) is releasing (OH^-) which implies it is basic in nature.
2. Hence it turns methyl orange in yellow colour.

Hence, the correct option is (B).