$N_2$ combines with metals to form:

Which of the following orders regarding the stability of phosphorus allotropes is correct?

The most stable trihalide of nitrogen is ..... .

What is the number of hydroxyl groups in pyrophosphoric acid?

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:

The strongest base is