Pure hydrogen sulphide is stored in a tank of $100 \ L$ capacity at $20 \ ^oC$ and $2 \ atm$ pressure. The mass of the gas will be ................. $g$.

$A$ river is flowing from east to west at a speed of $5\ m/min$. $A$ man on the south bank of the river,capable of swimming $10\ m/min$ in still water,wants to swim across the river in the shortest time. He should swim:

In a playground,there is a merry-go-round of mass $120 \ kg$ and radius $4 \ m$. The radius of gyration is $3 \ m$. $A$ child of mass $30 \ kg$ runs at a speed of $5 \ m/s$ tangent to the rim of the merry-go-round when it is at rest and then jumps on it. Neglecting friction,find the angular velocity of the merry-go-round and child in $rad/s$.

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. Tranquilizers	$I$. Anti blood clotting
$B$. Aspirin	$II$. Salvarsan
$C$. Antibiotic	$III$. Antidepressant drugs
$D$. Antiseptic	$IV$. Soframicine

Choose the correct answer from the options given below:

The structure of $XeOF_4$ is

Which of the following is an example of an unsaturated fatty acid?