Which of the following is a redox reaction?

In an alkaline medium,$ClO_2$ oxidizes $H_2O_2$ to $O_2$ and is reduced to $Cl^-$. How many moles of $H_2O_2$ will be oxidized by $1$ mole of $ClO_2$?

Observe the following reaction: $I_2 + 10 HNO_3 \rightarrow 2 HIO_3 + 10 NO_2 + 4 H_2O$. The equivalent weight of $HNO_3$ is (molar mass of $HNO_3 = M$).

How many moles of electrons are needed to convert one mole of nitrate ion to hydrazine?

The product of oxidation of $I^-$ ion by $MnO_4^-$ in alkaline medium is

For the reaction $I^{-} + ClO_3^{-} + H_2SO_4 \to Cl^{-} + HSO_4^{-} + I_2$ (no free $H^{+}$ is present),select the correct statement for the balanced equation (coefficients in smallest whole number ratio).