When cold and dilute $NaOH$ reacts with $Cl_2$, which of the following is formed?

Which of the following has the greatest reducing power?

$POCl_3$ is prepared by the reaction of:
$(I)$ $P_4 + SO_2Cl_2 \to$
$(II)$ $P_4 + SOCl_2 \to$
$(III)$ $PCl_5 + SO_2 \to$
$(IV)$ $PCl_5 + C_2H_5OH \to$

The correct order of the thermal stability of hydrogen halides $(HX)$ is:

Which of the following is not a peroxy acid?

Sea weed is employed as a source of manufacture of