What is the use of an indicator in titration ? Name the indicator used when sodium hydroxide is titrated against sulphuric acid

Explanation

**Step-by-Step Solution:**

1. **Understanding the Role of an Indicator in Titration:**
- An indicator is a substance that changes color at a specific pH level. In titration, it is used to visually signal the endpoint of the reaction, which is typically the point of neutralization between an acid and a base. The indicator helps to determine when the amount of acid is stoichiometrically equivalent to the amount of base.

2. **Identifying the Neutralization Point:**
- During titration, as the acid is added to the base (or vice versa), the pH of the solution changes. The indicator will change color at the neutralization point, which indicates that the reaction is complete. This allows the experimenter to stop adding the titrant (the solution of known concentration) at the right moment.

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