What is ‘A’ in the following reaction?
`2Fe^(3+) (aq) + Sn^(2+) (aq) rarr 2 Fe^(2+) (aq) + A`

Options

A. `Sn^(3+)(aq)`
B. `Sn^(4+) (aq)`
C. `Sn^(2+) (aq)`
D. `Sn(s)`

Answer

To determine what 'A' is in the reaction:

\[ 2Fe^{3+} (aq) + Sn^{2+} (aq) \rightarrow 2Fe^{2+} (aq) + A \]

we need to analyze the charges on both sides of the equation.

### Step 1: Calculate the total charge on the left-hand side (LHS)

The left-hand side consists of:
- \(2Fe^{3+}\): Each iron ion has a charge of +3, so for two iron ions:
\[ 2 \times (+3) = +6 \]
- \(Sn^{2+}\): The tin ion has a charge of +2:
\[ +2 \]

Now, adding these charges together:
\[ +6 + +2 = +8 \]

### Step 2: Calculate the total charge on the right-hand side (RHS)

The right-hand side consists of:
- \(2Fe^{2+}\): Each iron ion has a charge of +2, so for two iron ions:
\[ 2 \times (+2) = +4 \]
- Let’s denote the charge of 'A' as \(x\).

Now, the total charge on the right-hand side is:
\[ +4 + x \]

### Step 3: Set up the equation for charge conservation

According to the principle of charge conservation, the total charge on the left-hand side must equal the total charge on the right-hand side:
\[ +8 = +4 + x \]

### Step 4: Solve for \(x\)

To find \(x\), we rearrange the equation:
\[ x = +8 - +4 = +4 \]

### Conclusion

Therefore, 'A' must be:
\[ A = Sn^{4+} \]

### Final Answer
**A = Sn^{4+}**

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