$X + H_2SO_4 \to Y$ (colorless gas) and $Y + K_2Cr_2O_7 + H_2SO_4 \to$ green solution. Then $X$ and $Y$ are respectively ........

$N_2H_4 + IO_3^- + 2H^+ + Cl^- \to ICl + N_2 + 3H_2O$. What is the equivalent weight of the reductant in the above reaction?

$HNO_2$ acts as

Ferrous sulphate on strong heating gives:

Reduction of the metal centre in aqueous permanganate ion involves the following processes:
$(A)$ $3$ electrons in neutral medium
$(B)$ $5$ electrons in neutral medium
$(C)$ $3$ electrons in alkaline medium
$(D)$ $5$ electrons in acidic medium
Which of the following combinations is correct?

When $10 \, mL$ of an aqueous solution of $KMnO_{4}$ was titrated in acidic medium,an equal volume of $0.1 \, M$ aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of $KMnO_{4}$ in grams per litre is $...... \times 10^{-2}$. (Nearest integer)
[Atomic mass of $K=39, Mn=55, O=16$]