When $PbO_2$ reacts with conc. $HNO_3$,the gas evolved is:

Indicate the products $(X)$ and $(Y)$ in the following reactions:
$Na_{2}S + nS (n=1-8) \rightarrow (X)$
$Na_{2}SO_{3} + S \rightarrow (Y)$

Which of the following is acidic?

$H_2S$ is more acidic than $H_2O$,due to

When a colorless gas is passed through bromine water and it causes decolorization,which gas is it?

Which of the following statements is $INCORRECT$?