What are neutral oxides? Give examples.

The oxidation number of phosphorus varies from

Identify the correct order$(s)$ among the following:
$a. NH_3 > PH_3 > AsH_3$ (Thermal stability)
$b. NH_3 < PH_3 < AsH_3$ (Reducing power)
$c. NI_3 > NBr_3 > NCl_3$ (Lewis basic character)
$d. N_2O_5 > P_2O_5 > As_2O_5$ (Acidic character)
Select the correct option:

Regarding the hydrides of group $15$ elements $EH_{3}$ $(E = N, P, As, Sb, Bi)$, select the correct statement from the following:
$A$. The stability of hydrides decreases down the group.
$B$. The basicity of hydrides decreases down the group.
$C$. The reducing character increases down the group.
$D$. The boiling point increases down the group.
Choose the correct answer from the options given below:

Ionic radius (in $\mathring{A}$) of $As^{3+}$,$Sb^{3+}$ and $Bi^{3+}$ follow the order:

The number of $P-OH$ bonds and the oxidation state of the phosphorus atom in pyrophosphoric acid $(H_4P_2O_7)$ respectively are