Blister copper is refined by stirring molten impure metal with green logs of wood because such a wood liberates hydrocarbon gases (like $CH_4$). This process $X$ is called . . . . . . and the metal contains impurities of $Y$ is . . . . . . .

Six faces of an unbiased die are numbered with $2, 3, 5, 7, 11$ and $13$. If two such dice are thrown,then the probability that the sum on the uppermost faces of the dice is an odd number is

Identify the organism shown in the given figure.

Water is drained from a vertical cylindrical tank by opening a valve at the base of the tank. It is known that the rate at which the water level drops is proportional to the square root of water depth $y$,where the constant of proportionality $k > 0$ depends on the acceleration due to gravity and the geometry of the hole. If $t$ is measured in minutes and $k = \frac{1}{15}$,then the time to drain the tank if the water is $4 \text{ m}$ deep to start with is ......... $\text{min}$.

$A$ chloro compound of Vanadium has a spin-only magnetic moment of $1.73 \, BM$. This Vanadium chloride has the formula:

Which pair of oxyacids of phosphorus contains $P-H$ bonds?