Which of the following is not an oxidation-reduction reaction?

Assign $A, B, C, D$ from given type of reaction.
$2KI + CuSO_4 \longrightarrow CuI \downarrow + \frac{1}{2}I_2 + K_2SO_4$

$A_2O_x$ is oxidized to $AO_3^-$ by $MnO_4^-$ in acidic medium. If $1.5 \times 10^{-3} \text{ mole}$ of $A_2O_x$ requires $40 \text{ mL}$ of $0.03 \text{ M } KMnO_4$ solution in acidic medium,which of the following statement$(s)$ is/are correct?

Assertion $(A)$: Ferricyanide ion oxidises $H_2O_2$ to $H_2O$ in basic medium.
Reason $(R)$: Oxidation product of $H_2O_2$ is $O_2$. Which of the following is true?

Among $C$,$S$,and $P$,the element$(s)$ that produce$(s)$ $SO_{2}$ on reaction with hot conc. $H_{2}SO_{4}$ is / are

In which of the following reactions, chlorine acts as an oxidising agent?
$(i)$ $CH_3CH_2OH + Cl_2 \longrightarrow CH_3CHO + HCl$
(ii) $CH_3CHO + Cl_2 \longrightarrow CCl_3CHO + HCl$
(iii) $CH_4 + Cl_2 \stackrel{hv}{\longrightarrow} CH_3Cl + HCl$
The correct answer is