$e^{\log (\cosh^{-1} 2)}$ is equal to :

Give the number of electrons in the species $H_{2}^{+}$,$H_{2}$,and $O_{2}^{+}$.

Which of the following will not show geometrical isomerism?

If the direction cosines of two lines satisfy the equations $l+m+n=0$ and $2lm+2ln-mn=0$, then the acute angle between those two lines is

If $g$ is the acceleration due to gravity on the earth's surface,the gain in the potential energy of an object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth is

Which of the following is a biodegradable pollutant?