With which of the following does hydrogen combine directly?

If $\int \frac{e^x-1}{e^x+1} d x=f(x)+c$,then $f(x)$ is equal to

The displacements of two particles of same mass executing $SHM$ are represented by the equations $x_1 = 4 \sin \left(10 t + \frac{\pi}{6}\right)$ and $x_2 = 5 \cos (\omega t)$. The value of $\omega$ for which the energies of both the particles remain same is (in $\text{ unit}$)

When an excess of $NaOH$ solution is added to a solution of potassium alum,what do we obtain?

In the visible region,the dispersive powers and the mean angular deviations for crown and flint glass prisms are $\omega, \omega'$ and $d, d'$ respectively. The condition for getting deviation without dispersion when the two prisms are combined is

The electronic configuration of $Yb^{2+}$ is: