How many moles of $K_2Cr_2O_7$ are reduced by $1$ mole of $Sn^{2+}$?

To an acidified dichromate solution,a pinch of $Na_2O_2$ is added and shaken. What is observed?

$N_2H_4 + IO_3^- + 2H^+ + Cl^- \to ICl + N_2 + 3H_2O$. What is the equivalent weight of the reductant in the above reaction?

Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?

$2 \text{ mol}$ of $FeSO_4$ are oxidized by $X \text{ mol}$ of $KMnO_4$ whereas $2 \text{ mol}$ of $FeC_2O_4$ are oxidized by $Y \text{ mol}$ of $KMnO_4$. The ratio of $X$ and $Y$ is:

By passing $H_2S$ gas in acidified $KMnO_4$ solution,we get