Question 69. Chlorine undergoes disproportionation in alkaline medium as shown below:
\mathrm a\,{\mathrm{Cl}}_2+\mathrm b\,\mathrm{OH}^-\rightarrow\mathrm c\,\mathrm{ClO}^-+\mathrm d\,\mathrm{Cl}^-+\mathrm e\,{\mathrm H}_2\mathrm OThe values of \mathrm{a},\mathrm{b},\mathrm{c} and \mathrm{d} in the balanced redox reaction are:
(1) 1, 2, 1 and 1
(2) 2, 2, 1 and 3
(3) 3, 4, 4 and 2
(4) 2, 4, 1 and 3
Answer: (1)
Explanation:
In alkaline medium, chlorine undergoes disproportionation.
One chlorine atom is oxidised to hypochlorite ion.
The other chlorine atom is reduced to chloride ion.
The balanced reaction is:
{\mathrm{Cl}}_2+2\,\mathrm{OH}^-\rightarrow\mathrm{ClO}^-+\mathrm{Cl}^-+{\mathrm H}_2\mathrm OComparing with the given equation:
\mathrm{a}=1,\ \mathrm{b}=2,\ \mathrm{c}=1,\ \mathrm{d}=1Hence, the correct option is (1).