$KMnO_4$ reacts in alkaline medium as follows:
$2KMnO_4 + 2KOH \to 2K_2MnO_4 + H_2O + O$
What is the equivalent weight of $KMnO_4$?
(Atomic weights: $K = 39, Mn = 55, O = 16$)

Balance the following redox reactions using the oxidation number and ion-electron method:
$(1) H_2S + Fe^{3+} \to Fe^{2+} + S + H^{+}$
$(2) Cu + NO_3^{-} \to Cu^{2+} + NO_2$
$(3) Sn + NO_3^{-} + H^{+} \to Sn^{2+} + NH_4^{+} + H_2O$
$(4) As + NO_3^{-} + H^{+} \to AsO_4^{3-} + NO_2 + H_2O$

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

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_2CrO_4 + HCl \longrightarrow H_2Cr_2O_7 + NaCl$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Ba(N_3)_2 \xrightarrow{\Delta} Ba + 3N_2 \uparrow$

The volume of $0.02 \ M$ acidified acidified permanganate solution required for complete reaction of $60 \ mL$ of $0.01 \ M \ I^{-}$ ion solution to form $I_2$ in $mL$ is