Which among the following molecules has the lowest bond dissociation enthalpy?

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

The reactions of $Cl_2$ gas with cold-dilute and hot-concentrated $NaOH$ in water give sodium salts of two (different) oxoacids of chlorine,$P$ and $Q$,respectively. The $Cl_2$ gas reacts with $SO_2$ gas,in presence of charcoal,to give a product $R$. $R$ reacts with white phosphorus to give a compound $S$. On hydrolysis,$S$ gives an oxoacid of phosphorus $T$.
$1.$ $P$ and $Q$,respectively,are the sodium salts of
$(A)$ hypochlorous and chloric acids
$(B)$ hypochlorous and chlorous acids
$(C)$ chloric and perchloric acids
$(D)$ chloric and hypochlorous acids
$2.$ $R$,$S$ and $T$,respectively,are
$(A)$ $SO_2Cl_2, PCl_5$ and $H_3PO_4$
$(B)$ $SO_2Cl_2, PCl_3$ and $H_3PO_3$
$(C)$ $SOCl_2, PCl_3$ and $H_3PO_2$
$(D)$ $SOCl_2, PCl_5$ and $H_3PO_4$
Give the answer for question $1$ and $2$.

The correct group of halide ions which can be oxidised by oxygen in acidic medium is

When chlorine is passed over dry slaked lime at room temperature,the main reaction product is

Chlorine is allowed to react with an excess of ammonia. In this reaction,$1$ mole of chlorine can oxidize '$Z$' moles of $NH_3$. The value of '$Z$' is: