(i) Both tin and lead show two oxidation states of +2 and +4 due to inert pair effect. But the ipert pair effect is more prominent in case of Pb than in Sn. In other words, +2 oxidation state of Sn is less stable than its +4 oxidation state. Therefore, Sn (II) acts as a reducing agent and gets converted into more stable Sn (IV) by losing two electrons.
In contrast, +2 oxidation state of Pb is more stable than . its +4 oxidation state. In other words, Pb (II) does not lose electrons easily and hence does not act as a reducing agent.
(ii) Being a reducing agent, tin (II) chloride reduces mercuric chloride to mercurous chloride and ferric salts to ferrous salts.