When neutral or faintly alkaline $KMnO_4$ is treated with potassium iodide,iodide ion is converted into '$X$'. '$X$' is

The equivalent weight of $MnSO_4$ is half of its molecular weight when it is converted to

What is '$A$' in the following reaction?
$2Fe^{3+} + Sn^{2+} \to 2Fe^{2+} + A$

The following reaction occurs in acidic medium: $KMnO_4 + 8 H^{+} + 5 e^{-} \longrightarrow K^{+} + Mn^{2+} + 4 H_2O$. What is the equivalent weight of $KMnO_4$? (Molecular weight of $KMnO_4 = 158$)

$PbS + 4O_3 \,\to ?\,+\,4O_2$

Number of moles of $SnCl_2$ required for the reduction of $1$ mole of $K_2Cr_2O_7$ into $Cr^{3+}$ (in acidic medium) is: