Which of the following hydrides is the least stable?

Match the common name given in column $I$ with their taxonomic category family given in column $II$ and choose the correct combination from the options given below.

Column-$I$ (Common Name)	Column-$II$ (Taxonomic category- Family)
$A$. Man	$I$. Poaceae
$B$. Datura	$II$. Anacardiaceae
$C$. Mango	$III$. Solanaceae
$D$. Wheat	$IV$. Hominidae

The process of the isolation of a metal by dissolving the ore in a suitable chemical reagent followed by precipitation of the metal by a more electropositive metal is called:

Conifers differ from grasses in the

$A$ monoatomic gas is suddenly compressed to $(1/8)^{\text{th}}$ of its initial volume adiabatically. The ratio of the final pressure to initial pressure of the gas is (given $\gamma = 5/3$).

Four charges are placed at the circumference of a dial clock as shown in the figure. If the clock has only an hour hand, then the resultant force on a charge $q_0$ placed at the center points in the direction which shows the time as: (in $.30$)