Question

all decomposition reaction is not redox reaction but kclo3 is redox reaction why

Answer 1

Let me Justify:-

All Decomposition reaction are not redox reaction but it's not necessary that a decomposition reaction can't be redox,
Some Decomposition reactions can be redox too.......

Hope it'll Help You......

Have a great day.......

Answer 2

KClO3 is a redox reaction...
As,
2KClO3 >> 2KCl + 3 O2

in this case Cl goes from +5 to +1 and it's the oxidizing agent.
O goes from -2 to 0 and it's the reducing agent.

that's why it's a redox reaction...

hope it will help you....