Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$2BaCrO_4 \downarrow + 4HCl \longrightarrow 2BaCl_2 + H_2Cr_2O_7 + H_2O$

Consider the reactions:
$(a)$ $6 CO_{2(g)} + 6 H_{2}O_{(l)} \rightarrow C_{6}H_{12}O_{6(aq)} + 6 O_{2(g)}$
$(b)$ $O_{3(g)} + H_{2}O_{2(l)} \rightarrow H_{2}O_{(l)} + 2 O_{2(g)}$
Why is it more appropriate to write these reactions as:
$(a)$ $6 CO_{2(g)} + 12 H_{2}O_{(l)} \rightarrow C_{6}H_{12}O_{6(aq)} + 6 H_{2}O_{(l)} + 6 O_{2(g)}$
$(b)$ $O_{3(g)} + H_{2}O_{2(l)} \rightarrow H_{2}O_{(l)} + O_{2(g)} + O_{2(g)}$
Also,suggest a technique to investigate the path of the above $(a)$ and $(b)$ redox reactions.

The volume,in $mL$,of $0.02 \ M \ K_2Cr_2O_7$ solution required to react with $0.288 \ g$ of ferrous oxalate $(FeC_2O_4)$ in acidic medium is........
(Molar mass of $Fe = 56 \ g \ mol^{-1}$)

$Na_2S_2O_3$ is

Acidified potassium permanganate solution is decolourised by

On treating $SO_2$ with an aqueous solution of $KMnO_4$,the manganese ion reduces to