Question
When Cl2 gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from
-
zero to +1 and zero to -5
-
zero to -1 and zero to +5
-
zero to -1 and zero to +5
-
zero to +1 and zero to -3
Solution
B.
zero to -1 and zero to +5
When chlorine gas reacts with hot and concentrated NaOH solution, it disproportionates into Chloride (Cl-) and Chlorate (ClO3-) ions. 
