How many moles of electrons are required to reduce $2.5 \ mol$ of $Cr_2O_7^{2-}$ to $Cr^{3+}$?

When $SO_2$ gas is passed through an acidic solution of $K_2Cr_2O_7$,what is the change in the oxidation state of chromium?

What is the number of electrons transferred considering $Mn$ when $KMnO_4$ is converted into $Mn_2O_3$?

The product of oxidation of $I^{-}$ with $MnO_4^{-}$ in alkaline medium is

$KMnO_4$ reacts with ferrous sulphate according to the equation:
$MnO_4^- + 5Fe^{2+} + 8H^{+} \to Mn^{2+} + 5Fe^{3+} + 4H_2O$
Here,$10 \ mL$ of $0.1 \ M$ $KMnO_4$ is equivalent to:

Which among the following species acts as a self-indicator?