One litre of $0.15 \ M \ Na_2SO_3$ aqueous solution is mixed with $500 \ mL$ of $0.2 \ M \ K_2Cr_2O_7$ aqueous solution in acid medium. What is the concentration (in $mol \ L^{-1}$) of unreacted $K_2Cr_2O_7$ in the resultant solution?

Consider the reactions:
$2S_2O_3^{2-}{(aq)} + I_{2(s)} \to S_4O_6^{2-}{(aq)} + 2I^{-}{(aq)}$
$S_2O_3^{2-}{(aq)} + 2Br_{2(l)} + 5H_2O_{(l)} \to 2SO_4^{2-}{(aq)} + 4Br^{-}{(aq)} + 10H^{+}{(aq)}$
Why does the same reductant,thiosulphate,react differently with iodine and bromine?

$A$ white crystalline salt $[A]$ reacts with dilute $HCl$ to produce a suffocating gas $[B]$ and also forms a yellow precipitate. When gas $[B]$ is passed through acidified potassium dichromate,it turns the solution green,forming $[C]$. Identify $A, B$,and $C$ respectively.

$15 \ mL$ of aqueous solution of $Fe^{2+}$ in acidic medium completely reacted with $20 \ mL$ of $0.03 \ M$ aqueous $Cr_{2}O_{7}^{2-}$. The molarity of the $Fe^{2+}$ solution is ........... $\times 10^{-2} \ M$ (Round off to the Nearest Integer).

Which of the following reagents forms a green precipitate $(ppt)$ with $KI$?

When an acidic solution of $K_2Cr_2O_7$ is added to $Na_2SO_3$,it turns green. Which of the following compounds is formed in this reaction?