The reactive species in chlorine bleach is

The strongest reducing agent among the following is:

Write a note on hydrogen halides. Explain the reactivity of halogens with oxygen. $OR$ Write a note on oxides of halogens.

Fluorine exhibits only $-1$ oxidation state whereas other halogens exhibit $+1, +3, +5$ and $+7$ oxidation states also. Explain.

Which of the following properties of halogens increase with increasing atomic number?
$(I)$ Ionization energy $(II)$ Ionic radius
$(III)$ Bond energy of the $X_2$ molecule $(IV)$ Enthalpy of vaporisation

The reaction of $K_2Cr_2O_7$ with $NaCl$ and conc. $H_2SO_4$ gives