The indicator used in the titration of sodium carbonate with sulphuric acid is

Options

A. Phenolphthalein
B. Methyl organe
C. Potassium ferrocynide
D. Potassium ferricynide

Answer

To solve the question regarding the indicator used in the titration of sodium carbonate with sulfuric acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this titration are sodium carbonate (Na2CO3) and sulfuric acid (H2SO4).

2. **Understand the Reaction**:
- When sodium carbonate reacts with sulfuric acid, it undergoes a neutralization reaction, producing sodium sulfate (Na2SO4), water (H2O), and carbon dioxide (CO2).

3. **Determine the pH Range**:
- The titration of a weak base (sodium carbonate) with a strong acid (sulfuric acid) typically results in a solution that is acidic at the endpoint. The pH at the equivalence point will be less than 7.

4. **Choose the Appropriate Indicator**:
- For titrations where the endpoint is in the acidic range, an appropriate indicator is needed. Methyl orange is suitable because it changes color in the pH range of approximately 3.1 to 4.4, which is ideal for detecting the endpoint of the titration between sodium carbonate and sulfuric acid.

5. **Conclusion**:
- Therefore, the indicator used in the titration of sodium carbonate with sulfuric acid is **methyl orange**.

### Final Answer:
The indicator used in the titration of sodium carbonate with sulfuric acid is **methyl orange**.

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