The tendency to form monovalent compounds among the Group $13$ elements is correctly exhibited in:

Choose the correct statements about the hydrides of group $15$ elements.
$A$. The stability of the hydrides decreases in the order $NH_3 > PH_3 > AsH_3 > SbH_3 > BiH_3$
$B$. The reducing ability of the hydrides increases in the order $NH_3 < PH_3 < AsH_3 < SbH_3 < BiH_3$
$C$. Among the hydrides,$NH_3$ is strong reducing agent while $BiH_3$ is mild reducing agent.
$D$. The basicity of the hydrides increases in the order $NH_3 < PH_3 < AsH_3 < SbH_3 < BiH_3$
Choose the most appropriate from the option given below:

What are the products obtained when ammonia is reacted with excess chlorine?

$A + H_2O \to B + HCl$
$B + H_2O \to C + HCl$
Compound $(A), (B)$ and $(C)$ will be respectively

What is the lowest oxidation state possessed by phosphorus in its oxyacids?

Assertion : Molecular nitrogen is less reactive than molecular oxygen.
Reason : The bond length of $N_2$ is shorter than that of oxygen.