Aqueous solutions of $Na_2S_2O_3$ on reaction with $Cl_2$ gives

How many moles of $K_2Cr_2O_7$ can be reduced by $1 \ mol$ of $Sn^{2+}$?

$2MnO_4^{-} + 5H_2O_2 + 6H^{+} \to 2Z + 5O_2 + 8H_2O$. In this reaction $Z$ is

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.

What is $A$ in the following reaction $2Fe^{3+}_{(aq)} + Sn^{2+}_{(aq)} \to 2Fe^{2+}_{(aq)} + A$?

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?