Which of the following combinations of reagents does not undergo a redox reaction in an aqueous medium?

Assign $A, B, C, D$ from the given type of reaction.
$2KI + HgI_2 \downarrow \longrightarrow K_2[HgI_4]$

Which of the following compounds does not produce a green-coloured product on thermal decomposition?

The number of moles of $KMnO_4$ required to oxidize one equivalent of $KI$ in the presence of sulphuric acid is

Consider the following list of reagents:
Acidified $K_2Cr_2O_7$,alkaline $KMnO_4$,$CuSO_4$,$H_2O_2$,$Cl_2$,$O_3$,$FeCl_3$,$HNO_3$ and $Na_2S_2O_3$. The total number of reagents that can oxidise aqueous iodide to iodine is

$100 \ mL$ of $0.1 \ M$ $Fe^{2+}$ solution was titrated with $\frac{1}{60} \ M$ $Cr_2O_7^{2-}$ solution in acid medium. What is the volume (in $L$) of $Cr_2O_7^{2-}$ solution consumed?