Which of the following elements forms a strongly acidic oxide?

Ammonia is dried over

Which of the following oxides is the anhydride of orthophosphoric acid?

Identify the compound in which phosphorus exists in the oxidation state of $+1$.

Among $P_2O_5$,$As_2O_3$,$Sb_2O_3$,and $Bi_2O_3$,the most acidic oxide is

Based on the compounds of group $15$ elements,the correct statement$(s)$ is (are):
$(A)$ $Bi_2O_5$ is more basic than $N_2O_5$
$(B)$ $NF_3$ is more covalent than $BiF_3$
$(C)$ $PH_3$ boils at a lower temperature than $NH_3$
$(D)$ The $N-N$ single bond is stronger than the $P-P$ single bond