$A$ solution of colourless salt $H$ on boiling with excess $NaOH$ produces a non-flammable gas. The gas evolution ceases after sometime. Upon addition of $Zn$ dust to the same solution,the gas evolution restarts. The colourless salt$(s)$ $H$ is (are):

The colour of an iodine solution is discharged by shaking it with an aqueous solution of:

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$KI + AgNO_3 \longrightarrow AgI + KNO_3$

$KMnO_4$ (acidified) $+ HCl \rightarrow H_2O + X_{(g)},$ $X$ is a

The treatment of an aqueous solution of $3.74 \ g$ of $Cu(NO_3)_2$ with excess $KI$ results in a brown solution along with the formation of a precipitate. Passing $H_2S$ through this brown solution gives another precipitate $X$. The amount of $X$ (in $g$) is. . . . . [Given : Atomic mass of $H=1, N=14, O=16, S=32, K=39, Cu=63, I=127$ ]

Which of the following is $NOT$ a redox reaction?