Q.

It is because of inability of ns2 electrons of the valence shell to participate in bonding that                 [2017]

1 Sn2+ is oxidising while Pb4+ is reducing  
2 Sn2+ and Pb2+ are both oxidising and reducing  
3 Sn4+ is reducing while Pb4+ is oxidising  
4 Sn2+ is reducing while Pb4+ is oxidising  

Ans.

(4)

The inertness of s-subshell electrons towards bond formation is known as inert pair effect. This effect increases down the group thus, for Sn, +4 oxidation state is more stable, whereas, for Pb, +2 oxidation state is more stable, i.e., Sn2+ is reducing while Pb4+ is oxidising.