What is the equivalent weight of $K_2Cr_2O_7$ during the iodometric standardization of $Na_2S_2O_3$?

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 balanced chemical reaction: $IO_3^- + aI^- + bH^+ \to cH_2O + dI_2$,what are the values of $a, b, c$ and $d$ respectively?

Consider the following equations:
$2 Fe^{2+} + H_2O_2 \rightarrow x A + y B$
(in basic medium)
$2 MnO_4^{-} + 6 H^{+} + 5 H_2O_2 \rightarrow x' C + y' D + z' E$
(in acidic medium)
The sum of the stoichiometric coefficients $x, y, x', y'$ and $z'$ for products $A, B, C, D$ and $E,$ respectively,is............

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$S + HNO_3 \, (Dil.) \longrightarrow H_2SO_4 + NO \uparrow $

Which of the following reactions is a redox reaction?