When $KMnO_4$ reacts with $Br^-$ in a basic medium to give bromate ion,the oxidation state of $Mn$ changes from $7$ to . . . . . .

Which of the following is a redox reaction?

In acidic medium,potassium dichromate acts as an oxidant according to the equation,$Cr_2O_7^{2-} + 14H^{+} + 6e^- \to 2Cr^{3+} + 7H_2O$. What is the equivalent weight of $K_2Cr_2O_7$? (Molecular weight $= M$)

Assign $A, B, C, D$ from the given type of reaction:
$5CO(g) + I_2O_5(s) \longrightarrow 5CO_2(g) + I_2(s)$

In neutral medium,potassium permanganate oxidises $I^{-}$ to $X$. Identify $X$.

Consider the reactions:
$(a)$ $6CO_{2(g)} + 6H_2O_{(l)} \to C_6H_{12}O_{6(aq)} + 6O_{2(g)}$
$(b)$ $O_{3(g)} + H_2O_{2(l)} \to H_2O_{(l)} + 2O_{2(g)}$
Why is it more appropriate to write these reactions as:
$(a)$ $6CO_{2(g)} + 12H_2O_{(l)} \to C_6H_{12}O_{6(aq)} + 6H_2O_{(l)} + 6O_{2(g)}$
$(b)$ $O_{3(g)} + H_2O_{2(l)} \to H_2O_{(l)} + O_{2(g)} + O_{2(g)}$
Also,suggest a technique to investigate the reaction mechanism (path) of the above $(a)$ and $(b)$ redox reactions.