$1$ mole of $Fe^{2+}$ ions are oxidised to $Fe^{3+}$ ions with the help of $KMnO_4$ in acidic medium. How many moles of $KMnO_4$ are required?

The reaction of aqueous $KMnO_4$ with $H_2O_2$ in acidic conditions gives

Fluorine reacts with ice and results in the change:
$H_2O_{(s)} + F_{2(g)} \rightarrow HF_{(g)} + HOF_{(g)}$
Justify that this reaction is a redox reaction.

Observe the following reaction:
$xS_{8\text{(s)}} + yOH^{-}{_{\text{(aq)}}} \rightarrow zS^{2-}{_{\text{(aq)}}} + 2S_2O_3^{2-}{_{\text{(aq)}}} + 6H_2O_{\text{(l)}}$
Find the values of $x, y$ and $z$ respectively.

For the redox reaction $xP_4 + yHNO_3 \to H_3PO_4 + NO_2 + H_2O$,find the values of $x$ and $y$.

Balance the following ionic equations:
$1. Cr_{2}O_{7}^{2-} + H^{+} + I^{-} \to Cr^{3+} + I_{2} + H_{2}O$
$2. Cr_{2}O_{7}^{2-} + Fe^{2+} + H^{+} \to Cr^{3+} + Fe^{3+} + H_{2}O$
$3. MnO_{4}^{-} + SO_{3}^{2-} + H^{+} \to Mn^{2+} + SO_{4}^{2-} + H_{2}O$
$4. MnO_{4}^{-} + H^{+} + Br^{-} \to Mn^{2+} + Br_{2} + H_{2}O$