Which of the following is a redox reaction ?
A
$$ 2Na [Ag (CN)_2] + Zn \rightarrow Na_{2} [Zn(CN)_4] + 2Ag $$
B
$$ N_2O_5 + H_2O \rightarrow 2HNO_3 $$
C
$$ BaO_2 + H_2SO_4 \rightarrow BaSO_4 + H_2O_2 $$ 9
D
$$ AgNO_3 + KI \rightarrow AgI + KNO_3 $$
Correct option is A. $$ 2Na [Ag (CN)_2] + Zn \rightarrow Na_{2} [Zn(CN)_4] + 2Ag $$
$$ 2Na [Ag (CN)_2] + Zn \rightarrow Na_{2} [Zn(CN)_4] + 2Ag $$
this is showing redox reaction