Discussion Forum



1)

Which among the following equations represents in the reduction reaction taking place in lead accumulator at the positive electrode, while it is being used as a source of electrical energy?


A) $Pb\rightarrow Pb^{2+}$

B) $ Pb^{4+}\rightarrow Pb$

C) $ Pb^{2+}\rightarrow Pb$

D) $ Pb^{4+}\rightarrow Pb^{2+}$

Answer:

Option D

Explanation:

 The reaction  involved for lead accumulator during discharging i.e, when cell is in the use are

At anode:  $Pb(s)+HSO_{4}^{-}(aq)\rightarrow PbSO_{4}(s)+H^{+}+2e^{-}$

 At cathode:  $PbO_{2}(s)+3H^{+}(aq)+HSO_{4}^{-}(aq)+2e^{-}\rightarrow PbSO_{4}(s)+2H_{2}O(l)$

 Overall reaction :    $ Pb(s)+PbO_{2}(s)+2H^{+}+2HSO_{4}^{-}(aq)\rightarrow 2PbSO_{4}(s)+2H_{2}O(l)$