Give reasons : A. Ga^(3+) salts are better reducing agent while Tl^(3+) salts are better oxidising agent.

A. i. Both gallium (Ga) and thallium (Tl) belong to group 13.

ii. Ga is lighter element compared to thallium Tl. 

Therefore,

Its +3 oxidation state is stable. 

Thus, 

Ga+ loses two electrons and get oxidized to Ga³⁺. 

Hence, 

Ga+ salts are better reducing agent.

iii. Thallium is a heavy element. 

Therefore, due to the inert pair effect, 

Tl forms stable compounds in +1 oxidation state. 

Thus,

Tl³⁺ salts get easily reduced to Tl¹⁺ by accepting two electrons. 

Hence,

Tl³⁺ salts are better oxidizing agent.

[Note : This question is modified so as to apply the appropriate textual concept.]

B. i. Pb has electronic configuration [Xe] 4f¹⁴5d¹⁰6s²6p².

ii. Due to poor shielding of 6s² electrons by inner d and f electrons, it is difficult to remove 6s² electrons (inert pair).

iii. Thus, due to inert pair effect, 

+2 oxidation state is more stable than +4 oxidation state. 

Hence, 

PbCl₄ is less stable than PbCl₂.