What is the equivalent weight of the oxidizing agent in the following reaction?
$SO_2 + 2H_2S \to 3S + 2H_2O$

In which of the following conversions does a blue colour appear?

In order to oxidize a mixture of one mole of each of $FeC_2O_4$,$Fe_2(C_2O_4)_3$,$FeSO_4$ and $Fe_2(SO_4)_3$ in acidic medium,the number of moles of $KMnO_4$ required is

$20 \, mL$ of $0.02 \, M \, K_2Cr_2O_7$ solution is used for the titration of $10 \, mL$ of $Fe^{2+}$ solution in the acidic medium. The molarity of $Fe^{2+}$ solution is ........... $\times 10^{-2} \, M$ (Nearest Integer).

$KMnO_4$ oxidises $S_2O_3^{2-}$ to $SO_4^{2-}$ in medium $x$ and $NO_2^-$ to $NO_3^-$ in medium $y$. $x$ and $y$ are respectively:

In which of the following redox reactions is a precipitate $NOT$ formed?