1. Cl2 bleaches by oxidation, while SO2 does it by reduction. The reduced product gets oxidise again and the colour is regained back.
2. Aluminium bromide exists as a dimer, Al2Br6 . In this structure, each aluminium atom forms one coordinate bond by accepting a lone pair of electrons from the bromine atom of another aluminium bromide molecule and thus complete the octet of electrons. Due to lack of free electrons, molten aluminium bromide is a poor conductor of electricity.
3. Nitric oxide reacts with air and oxidised into NO2 which is brown in colour.
2NO + O2 → 2NO2
4. In solid state PCl5 exists as [PCl4]+ [PCl6]- and hence it is ionic in nature. Due to its ionic nature, it conducts current on fusion.
5. N atom in ammonia has lone pair of electrons which can coordinate with other atoms or cations required for the stability of electron pair.