On heating ammonium dichromate,the gas evolved is

Ammonia is liberated in the reaction of

Which among the following group-$15$ elements forms hydrogen bonding in its hydride compounds?

Given below are the two statements: one is labeled as Assertion $(A)$ and the other is labeled as Reason $(R)$.
Assertion $(A)$: There is a considerable increase in covalent radius from $N$ to $P$. However,from $As$ to $Bi$,only a small increase in covalent radius is observed.
Reason $(R)$: Covalent and ionic radii in a particular oxidation state increase down the group.
In the light of the above statements,choose the most appropriate answer from the options given below:

Match $List-I$ with $List-II$,match the gas evolved during each reaction.

$List-I$	$List-II$
$A$. $(NH_4)_2Cr_2O_7 \xrightarrow{\Delta}$	$I$. $H_2$
$B$. $KMnO_4 + HCl \rightarrow$	$II$. $N_2$
$C$. $Al + NaOH + H_2O \rightarrow$	$III$. $O_2$
$D$. $NaNO_3 \xrightarrow{\Delta}$	$IV$. $Cl_2$

Choose the correct answer from the options given below.

Find the correct statements related to group $15$ hydrides.
$A$. Reducing nature increases from $NH_3$ to $BiH_3$
$B$. Tendency to donate lone pair of electrons decreases from $NH_3$ to $BiH_3$
$C$. The stability of hydrides decreases from $NH_3$ to $BiH_3$
$D$. $HEH$ bond angle decreases from $NH_3$ to $SbH_3$ ($E$ = Elements of group $15$)
Choose the correct answer from the options given below: