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

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?

$200 \ mL$ of $x \times 10^{-3} \ M$ potassium dichromate $(K_2Cr_2O_7)$ is required to oxidise $750 \ mL$ of $0.6 \ M$ Mohr's salt $(FeSO_4 \cdot (NH_4)_2SO_4 \cdot 6H_2O)$ solution in acidic medium. Here $x =$ ?

Acidified $KMnO_4$ is decolourised by:

$CO_2$ and $SO_2$ gases can be distinguished by using:

The number of moles of $KMnO_4$ reduced by $1 \ mol$ of $KI$ in basic medium is .............