Chlorine acts as a bleaching agent only in the presence of which of the following?

Among the following,the number of halide$(s)$ which is/are inert to hydrolysis is ..........
$(A)$ $BF_3$
$(B)$ $SiCl_4$
$(C)$ $PCl_5$
$(D)$ $SF_6$

Among the following,the number of compounds that can react with $PCl_5$ to give $POCl_3$ is $O_2, CO_2, SO_2, H_2O, H_2SO_4, P_4O_{10}$.

Concentrated $H_2SO_4$ cannot be used to prepare $HBr$ from $NaBr$,because it

Give two examples to show the anomalous behaviour of fluorine.

$Cl_2$ gas is dried over which of the following?