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?

Assign $A, B, C, D$ from the given type of reaction.
$2NaI + 2H_2SO_4 \,(Conc.) \longrightarrow Na_2SO_4 + I_2 + SO_2 + 2H_2O$

In the equation,$BiO_3^{-} + 6H^{+} + xe^{-} \rightarrow Bi^{3+} + 3H_2O$. What is the value of $x$?

What are $x, y$ and $z$ respectively in the following reaction?
$xFe^{2+}{_{\text{(aq)}}} + yH^{+}{_{\text{(aq)}}} + zCr_2O_7^{2-}{_{\text{(aq)}}} \rightarrow \frac{y}{2}H_2O_{\text{(l)}} + xFe^{3+}{_{\text{(aq)}}} + 2zCr^{3+}{_{\text{(aq)}}}$

Balance the following redox reactions using the oxidation number and ion-electron method:
$(1) H_2S + Fe^{3+} \to Fe^{2+} + S + H^{+}$
$(2) Cu + NO_3^{-} \to Cu^{2+} + NO_2$
$(3) Sn + NO_3^{-} + H^{+} \to Sn^{2+} + NH_4^{+} + H_2O$
$(4) As + NO_3^{-} + H^{+} \to AsO_4^{3-} + NO_2 + H_2O$

When thiosulphate ion is oxidised by iodine,which one of the following ions is produced?