List of top Chemistry Questions on Periodicity of Elements

Consider the following sequence of reactions:

4-nitrotoluene
Assuming that the reaction proceeds to completion, then 137 mg of 4-nitrotoluene will produce_______ mg of B. (Given molar mass in g mol⁻¹ H: 1, C: 12, N: 14, O: 16, Br: 80)}

It is noticed that $Pb^{2+}$ is more stable than $Pb^{4+}$ but $Sn^{2+}$ is less stable than $Sn^{4+}$. Observe the following reactions. 
$PbO_2 + Pb \to 2PbO ; \Delta_rG^\circ(1)$ 
$SnO_2 + Sn \to 2SnO ; \Delta_rG^\circ(2)$ 
Identify the correct set from the following