Question

Which of the following are true for an acid-base titration?

• A. Indicators catalyse the acid-base reactions by relasing or accepting $H^{\oplus }$ ions
• B. Indicators do not significantly affect the pH of the solution to which they are added
• C. Acid-base reactions do not occur in the absence of indicators
• D. Indicators have different colours in dissociated and undissociated forms

Answer 1

Answer: (B), (D)

Indicators have different colours in dissociated and undissociated forms
Indicators do not significantly affect the pH of the solution to which they are added

A Acid base titration done in the presence of indicators just to find out equivalence or end point of reaction. Indicators did not play any role to catalyse a reaction.

A - False.

B. Indicators are weak acid or base which are added to a titration reaction in a very small amount which did not affect $pH$ of that solution.

B - True.

C. All acid base reaction did not require indicators for completion.

C - False.

D. At different $pH$ values indicators are ionized and change its colour.

D - True.