Acidification of chromate gives ' $Z$ '. The oxidation state of chromium in ' $Z$ ' is

100 mL of $0.1 \mathrm{M} \mathrm{Fe}^{2+}$ solution was titrated with $\frac{1}{60} \mathrm{M}$ $\mathrm{Cr}_2 \mathrm{O}_7^{2-}$ solution in acid medium. What is the volume (in L ) of $\mathrm{Cr}_2 \mathrm{O}_7^{2-}$ solution consumed ?

Which of the following reactions of $\mathrm{KMnO}_4$ occurs in acidic medium ?

Which of the following occurs with $\mathrm{KMnO}_4$ in neutral medium?