Students were asked to study the reaction between barium chloride and sodium sulphate. Four different reports of the experiment are given below. Choose the correct one.

Options

A. `{:("Procedure","Observation"),("Mix powder of ","The colour of the"), ("barium chloride and", "mixture becomes yellow."),("sodium sulphate.",):}`
B. `{:("Procedure","Observation"), ("Mix solution of", "White precipitate"),("barium chloride to", "is formed"),( "the solution of",),("sodium sulphate.",):}`
C. `{:("Procedure","Observation"), ("Add solution of ","Solution becomes"),("barium chloride to", "turbid."),("sodium sulphate powder.",):}`
D. `{:("Procedure","Observation"), ("Add powder of","The colour of the"),("barium chloride to", "mixture becomes bluish"), ("sodium sulphate solution.", "green."):}`

Explanation

To solve the problem regarding the reaction between barium chloride and sodium sulfate, we can follow these steps:

### Step 1: Write the Chemical Equation
The first step is to write the balanced chemical equation for the reaction between barium chloride (BaCl₂) and sodium sulfate (Na₂SO₄).

**Chemical Equation:**
\[ \text{BaCl}_2 (aq) + \text{Na}_2\text{SO}_4 (aq) \rightarrow \text{BaSO}_4 (s) + 2\text{NaCl} (aq) \]

### Step 2: Identify the Products
In the reaction, barium sulfate (BaSO₄) is formed as a solid precipitate, while sodium chloride (NaCl) remains in the aqueous solution.

### Step 3: Observe the Precipitate
When barium chloride and sodium sulfate solutions are mixed, a white precipitate of barium sulfate is formed. This is a key observation in the experiment.

### Step 4: Analyze the Reports
Now, we need to analyze the four reports given by the students regarding the experiment:
1. The solution turns yellow.
2. A white precipitate is formed.
3. The solution becomes turbid.
4. The color of the mixture becomes bluish-green.

### Step 5: Determine the Correct Report
From our understanding of the reaction:
- The solution does not turn yellow (Report 1 is incorrect).
- A white precipitate of barium sulfate is indeed formed (Report 2 is correct).
- The solution does not become turbid; it is clear except for the precipitate (Report 3 is incorrect).
- The color of the mixture does not change to bluish-green (Report 4 is incorrect).

### Conclusion
The correct report of the experiment is the one stating that a white precipitate is formed.

**Final Answer:**
The correct report is: **A white precipitate is formed.**

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