Question

Among the following, select the disproportionation reaction?
(i) $2Pb(NO_{3})_{2} \to 2PbO + 4NO_{2} +Io_{2}$
(ii)$I_{2}+I^{-}+IO^{-}_{3}$
(iii) $3 Cl_{2} + 6NaOH \to 5NaCl + NaClO_{3} + 3H_{2}O$
(iv) $P_{4} + 3NaOH + 3H_{2}O \to 3NaH_{2}PO_{2}+PH_{3}$

• A. (i), (ii), (iii)
• B. (ii), (iii), (iv)
• C. (i), (iii), (iv)
• D. All of these

Answer 1

Answer: (B)

A reaction in which the same species is simultaneously oxidised as well as reduced is called a disproportionation reaction
(ii) $\overset{0}{I_{2}} \to \overset{-1}{I^{-}}+\overset{+5}{IO_{3}}$
(iii) $3 \overset{0}{Cl_{2}}+6NaOH \to 5Na \overset{-1}{Cl}+Na \overset{+5}{Cl}O_{3}+3H_{2}O$
(iv) $\overset{0}{P_{4}}+3NaOH+3H_{2}O\to 3NaH_{2} \overset{+1}{P}O_{4}+\overset{-3}{P}H_{3}$