This video lecture from The Halogens and The Noble Gases (F.Sc. second year Chemistry) covers: Reactions in which oxidation and reduction take place in a chemical specie at the same time. chorine;s reaction with hot and cold NaOH and formation of hypochlorite ions.An intoduction to comproportionation reactions. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.