Two gases $A$ and $B$ having the same volume,effuse through an orifice in $30 \ min$ and $10 \ min$ respectively. The molar mass of $A$ is $162$. The molar mass of $B$ will be

For better survival of the human population,which of the following steps is most important?

Which one of the taxonomic aids can give comprehensive account of complete compiled information of any one genus or family at a particular time?

There are $n$ distinct points on the circumference of a circle. The number of pentagons that can be formed with these points as vertices is equal to the number of possible triangles. Then the value of $n$ is

Which compound has the highest covalent character?

The image of the point $(1, 2, -1)$ on the plane containing the line $\frac{x+1}{-3}=\frac{y-3}{2}=\frac{z+2}{1}$ and the point $(0, 7, -7)$ is: