$Na_2S_2O_3$ is

Assign $A, B, C, D$ from the given type of reaction.
$CrCl_3$ $(aq)$ + $ZnSO_4$ $(aq)$ $\longrightarrow$ No reaction

What is the oxidation state of chromium in the final product when $KI$ reacts with acidified potassium dichromate solution?

Which of the following reduction products of $NO_3^-$ involves the maximum number of moles of electrons taken up per mole of $NO_3^-$?

$50 \ cm^{3}$ of $0.04 \ M \ K_{2}Cr_{2}O_{7}$ in acidic medium oxidizes a sample of $H_{2}S$ gas to sulphur. The volume of $0.03 \ M \ KMnO_{4}$ required to oxidize the same amount of $H_{2}S$ gas to sulphur in acidic medium is: (in $cm^{3}$)

The oxidation state of copper changes when aqueous copper $(II)$ ions react with
$(I)$ $NaOH_{(aq)}$
$(II)$ $Fe_{(s)}$
$(III)$ $KI_{(aq)}$