Which component is most active for bleaching action in bleaching powder?

Which of the following reactions proves the chlorinating property of phosphorus pentachloride?

Name the gaseous products from the following $A$ and $B$ reactions,respectively.
$A.$ Hydrochloric acid is added to sodium sulphide.
$B.$ Concentrated sulphuric acid is added to a mixture of sodium chloride and manganese dioxide.

Which of the following is prepared by the electrolytic method?

Which of the following statements regarding the properties of halogens are correct?
$(a)$ Due to small size and strong inter-electronic repulsion,the electron gain enthalpy of fluorine is less negative than that of chlorine.
$(b)$ Iodine has a different physical state and colour compared to other members of the group.
$(c)$ Fluorine does not show a positive oxidation state.
$(d)$ In $X_{2(g)} + H_2O(l) \rightarrow HX(aq) + HOX(aq)$ (where $X = Cl$ or $Br$).

Which of the following halogens is most easily reduced?