By passing $H_2S$ gas in acidified $KMnO_4$ solution,we get

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$FeCl_3 + Na_3PO_4 \longrightarrow FePO_4 \downarrow + 3NaCl$

Which one of the following reactions is not possible?

$50 \ cm^{3}$ of $0.04 \ M \ K_{2}Cr_{2}O_{7}$ in acidic medium oxidizes a sample of $H_{2}S$ gas to sulphur. The volume of $0.03 \ M \ KMnO_{4}$ required to oxidize the same amount of $H_{2}S$ gas to sulphur in acidic medium is: (in $cm^{3}$)

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 $K=39, Mn=55, O=16$]

Which of the following reactions are correct? (Ignore balancing of the reactions)
$(I)$ $Al + NaOH \xrightarrow{\Delta} NaAlO_2 + H_2$
$(II)$ $P_4 + NaOH + H_2O \to NaH_2PO_2 + PH_3$
$(III)$ $S + NaOH \to Na_2S_2O_3 + Na_2S + H_2O$