Assign $A, B, C, D$ from the given type of reaction.
$Mg_{(s)} + 2H_2O_{(l)} \xrightarrow{\text{Warm}} Mg(OH)_{2(aq)} + H_{2(g)} \uparrow$

Which of the following is a redox reaction?

Which of the following reactions of $KMnO_4$ occurs in acidic medium?

The number of electrons required to reduce chromium completely in $Cr_2O_7^{2-}$ to $Cr^{3+}$ in acidic medium is:

Balance the following redox reactions by the ion-electron method:
$(a)$ $MnO_{4(aq)}^- + I_{(aq)}^- \to MnO_{2(s)} + I_{2(s)}$ (in basic solution)
$(b)$ $MnO_{4(aq)}^- + SO_{2(g)} \to Mn_{(aq)}^{2+} + HSO_{4(aq)}^-$ (in acidic solution)
$(c)$ $H_2O_{2(aq)} + Fe_{(aq)}^{2+} \to Fe_{(aq)}^{3+} + H_2O_{(l)}$ (in acidic solution)
$(d)$ $Cr_2O_7^{2-} + SO_{2(g)} \to Cr_{(aq)}^{3+} + SO_{4(aq)}^{2-}$ (in acidic solution)

Calculate the equivalent weight of $KMnO_4$ in acidic,basic,and neutral media.