Assertion: Reaction between barium chloride and sodium sulphate is a double displacement and precipitation reaction.
Reason: Reaction between barium chloride and sodium sulphate involves the exchange of ions between the reactants and a white precipitate of barium sulphate is formed.

Options

A. If both assertion and reason are time and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in this reaction are barium chloride (BaCl₂) and sodium sulfate (Na₂SO₄).

2. **Write the Chemical Equation**:
When barium chloride reacts with sodium sulfate, the products formed are barium sulfate (BaSO₄) and sodium chloride (NaCl). The balanced chemical equation is:
\[ \text{BaCl}_2 + \text{Na}_2\text{SO}_4 \rightarrow \text{BaSO}_4 + 2\text{NaCl} \]

3. **Determine the Type of Reaction**:
- **Double Displacement Reaction**: In this reaction, the barium ions (Ba²⁺) and sodium ions (Na⁺) exchange places with sulfate ions (SO₄²⁻) and chloride ions (Cl⁻). This exchange of ions is characteristic of a double displacement reaction.
- **Precipitation Reaction**: A white precipitate of barium sulfate (BaSO₄) is formed as a result of this reaction, indicating that it is also a precipitation reaction.

4. **Conclusion**:
Both the assertion and reason provided in the question are correct. The reaction between barium chloride and sodium sulfate is indeed a double displacement and precipitation reaction, as it involves the exchange of ions and results in the formation of a white precipitate of barium sulfate.