$KMnO_4$ acts as an oxidising agent in acidic medium. The number of moles of $KMnO_4$ that will be needed to react with one mole of sulphide ion $(S^{2-})$ in acidic solution is . . . . . . (in $/5$)?

Assign $A, B, C, D$ from given type of reaction.
$Na_{(s)} + H_2O_{(l)} \xrightarrow{R.T.} NaOH + H_2 \uparrow $

How many electrons are involved in the following redox reaction?
$Cr_2O_7^{2-} + Fe^{2+} + C_2O_4^{2-} \to Cr^{3+} + Fe^{3+} + CO_2$ (Unbalanced)

Consider the following statements:
In the chemical reaction:
$MnO_2 + 4HCl \to MnCl_2 + 2H_2O + Cl_2$
$(1)$ Manganese ion is oxidised
$(2)$ Manganese ion is reduced
$(3)$ Chloride ion is oxidised
$(4)$ Chloride ion is reduced.
Which of these statements are correct?

In the given chemical reaction,colors of the $Fe^{2+}$ and $Fe^{3+}$ ions,are respectively :
$5 Fe^{2+} + MnO_{4}^{-} + 8 H^{+} \rightarrow Mn^{2+} + 4 H_{2} O + 5 Fe^{3+}$

In the half-reaction $Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,the equivalent weight of $Cr_2O_7^{2-}$ is obtained by dividing its molecular weight by: