Read the given passage and answer the questions.
P, Q and R are three elements which undergo chemical reactions according to the following equations.
(i) `P_(2)O_(3) +2Q to Q_(2)O_(3) +2P`
(ii) `3RSO_(4) +2Q to Q_(2)(SO_(4))_(3) +3R`
(iii) `3RO +2P to P_(2) O_(3) +3R`
`Na_(2)SO_(4) (aq) +BaCl_(2)(aq) to BaSO_(4)(s) +2NaCl (aq)`
The above reaction is an example of:

Options

A. Double displacement reaction.
B. Displacement reaction.
C. Can be both.
D. None of the above.

Explanation

To solve the question regarding the type of reaction represented by the equation:

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

we will analyze the reaction step by step.

### Step 1: Identify the Reactants and Products
In the given reaction, the reactants are sodium sulfate (\( \text{Na}_2\text{SO}_4 \)) and barium chloride (\( \text{BaCl}_2 \)). The products formed are barium sulfate (\( \text{BaSO}_4 \)) and sodium chloride (\( \text{NaCl} \)).

### Step 2: Analyze the Reaction Type
Next, we need to determine what is happening during the reaction. The sodium ions (\( \text{Na}^+ \)) from sodium sulfate and the barium ions (\( \text{Ba}^{2+} \)) from barium chloride are exchanging places with the sulfate ions (\( \text{SO}_4^{2-} \)) and chloride ions (\( \text{Cl}^- \)).

### Step 3: Identify the Exchange of Ions
In this reaction:
- The barium ions (\( \text{Ba}^{2+} \)) combine with sulfate ions (\( \text{SO}_4^{2-} \)) to form barium sulfate (\( \text{BaSO}_4 \)), which is a solid precipitate.
- The sodium ions (\( \text{Na}^+ \)) combine with chloride ions (\( \text{Cl}^- \)) to form sodium chloride (\( \text{NaCl} \)), which remains in the aqueous state.

### Step 4: Conclusion on Reaction Type
Since the ions are exchanging partners, this type of reaction is classified as a **double displacement reaction** (also known as a double replacement reaction). In this reaction, two compounds exchange ions to form two new compounds.

### Final Answer
The above reaction is an example of a **double displacement reaction**.

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