$Mn^{2+}$ can be converted into $Mn^{7+}$ by reacting with

The reaction $H_2S + H_2O_2 \to 2H_2O + S$ shows:

Starch-iodide paper is used for the test of:

Which of the following groups of molecules act both as an oxidising agent as well as a reducing agent?

Which of the following elements never acts as a reducing agent?

$(A) \ HOCl + H_2O_2 \rightarrow H_3O^{+} + Cl^{-} + O_2$
$(B) \ I_2 + H_2O_2 + 2 OH^{-} \rightarrow 2 I^{-} + 2 H_2O + O_2$
Choose the correct option.