The number of moles of oxalate ions $(C_2O_4^{2-})$ oxidized by one mole of permanganate ions $(MnO_4^-)$ in acidic medium is

In the balanced reaction $x\,MnO_4^- + y\,H_2O \to 2Mn^{2+} + 5H_2O + 9O_2 + z\,e^-$,what are the values of $x$,$y$,and $z$?

In the reaction
$x BrO_3^- + y Cr^{3+} + z H_2O \to Br_2 + CrO_4^{2-} + H^{+}$
the coefficients $x, y, z$ are

The following reaction occurs in acidic medium: $KMnO_4 + 8 H^{+} + 5 e^{-} \longrightarrow K^{+} + Mn^{2+} + 4 H_2O$. What is the equivalent weight of $KMnO_4$? (Molecular weight of $KMnO_4 = 158$)

Balance the following ionic equations:
$1. Cr_{2}O_{7}^{2-} + H^{+} + I^{-} \to Cr^{3+} + I_{2} + H_{2}O$
$2. Cr_{2}O_{7}^{2-} + Fe^{2+} + H^{+} \to Cr^{3+} + Fe^{3+} + H_{2}O$
$3. MnO_{4}^{-} + SO_{3}^{2-} + H^{+} \to Mn^{2+} + SO_{4}^{2-} + H_{2}O$
$4. MnO_{4}^{-} + H^{+} + Br^{-} \to Mn^{2+} + Br_{2} + H_{2}O$

What is $A$ in the following reaction $2Fe^{3+}_{(aq)} + Sn^{2+}_{(aq)} \to 2Fe^{2+}_{(aq)} + A$?