Question

Chlorine undergoes disproportionation in alkaline medium as shown below:
\(a \, \text{Cl}_2(g) + b \, \text{OH}^-(\text{aq}) \rightarrow c \, \text{ClO}^-(\text{aq}) + d \, \text{Cl}^-(\text{aq}) + e \, \text{H}_2\text{O}(\text{l})\)
The values of \( a \), \( b \), \( c \), and \( d \) in a balanced redox reaction are respectively:

• A. 1, 2, 1, and 1
• B. 2, 2, 1, and 3
• C. 2, 2, 1, and 3
• D. 2, 2, 1, and 3

Answer 1

The Correct Option is A

To find the values of \(a\), \(b\), \(c\), and \(d\) in the balanced equation of chlorine disproportionation in an alkaline medium, let's follow these steps: 

1. Disproportionation involves the simultaneous oxidation and reduction of the same element. In this case, chlorine (\(\text{Cl}_2\)) is both reduced to chloride ions (\(\text{Cl}^-\)) and oxidized to hypochlorite ions (\(\text{ClO}^-\)).
2. First, write the half-reactions for oxidation and reduction:

• Reduction: \(\text{Cl}_2 + 2e^- \rightarrow 2\text{Cl}^-\)
• Oxidation: \(\text{Cl}_2 + 2\text{OH}^- \rightarrow 2\text{ClO}^- + 2\text{H}_2\text{O} + 2e^-\)

1. Combine the half-reactions. Make sure the number of electrons lost is equal to the number of electrons gained to maintain electron balance:

• Overall equation after canceling electrons: \( \text{Cl}_2 + 2\text{OH}^- \rightarrow \text{ClO}^- + \text{Cl}^- + \text{H}_2\text{O} \)

1. Balancing the atoms and charges, we have:

From the combined reaction:

• The coefficient of \(\text{Cl}_2\) (\(a\)) is 1.
• The coefficient of \(\text{OH}^-\) (\(b\)) is 2.
• The coefficient of \(\text{ClO}^-\) (\(c\)) is 1.
• The coefficient of \(\text{Cl}^-\) (\(d\)) is 1.

1. Thus, the balanced redox reaction coefficients are \(a = 1\), \(b = 2\), \(c = 1\), and \(d = 1\).

Therefore, the correct set of coefficients is 1, 2, 1, and 1, which matches with the given option: 1, 2, 1, and 1.

Answer 2

The disproportionation reaction of chlorine in alkaline medium can be balanced as follows. Chlorine (Cl₂) is both reduced and oxidized:

Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O

Thus, the values of a, b, c, and d are 1, 2, 1, and 1 respectively.

So, the correct answer is: Option (1)