For the reaction $3K_2MnO_4 + 2H_2SO_4 \rightarrow 2KMnO_4 + K_2SO_4 + MnO_2 + 2H_2O$,what is the stoichiometric ratio of the reactants $K_2MnO_4$ to $H_2SO_4$?

In the reduction of dichromate by $Fe(II)$,the number of electrons involved per chromium atom is:

Which of the following is a redox reaction?
$(i) \, CdCl_2 + 2 KOH \longrightarrow Cd(OH)_2 + 2 KCl$
$(ii) \, BaCl_2 + K_2SO_4 \longrightarrow BaSO_4 + 2 KCl$
$(iii) \, CaCO_3 \longrightarrow CaO + CO_2$
$(iv) \, 2 Ca + O_2 \longrightarrow 2 CaO$

In alkaline medium,the reaction of hydrogen peroxide with potassium permanganate produces a compound in which the oxidation state of $Mn$ is $....$

Assign $A, B, C, D$ from the given type of reaction.
$3PbS + 8HNO_3 \text{ (dil.)} \longrightarrow 3Pb(NO_3)_2 + 3S \downarrow + 2NO + 4H_2O$

In an acidic medium,the dichromate ion oxidizes the ferrous ion to the ferric ion. If the molar mass of potassium dichromate is $294 \, g/mol$,what is its equivalent mass?