Which of the following is not an isotope of hydrogen?

The freezing point depression of a $0.001 \ m$ aqueous solution of $[Pt(NH_3)_4 Cl_4]$ is $0.0054^{\circ} C$. If $K_f$ for water is $1.80 \ K \ kg \ mol^{-1}$,determine the correct formula of the complex.

An open pipe of length $33 \ cm$ resonates to a frequency of $1000 \ Hz$. The mode of vibration is: (velocity of sound $= 330 \ m/s$)

The maximum tension a rope can withstand is $60 ~kg-wt$. The ratio of maximum acceleration with which two boys of masses $20 ~kg$ and $30 ~kg$ can climb up the rope at the same time is

We have two spheres,one of which is a hollow shell and the other is solid. They have identical masses and moments of inertia about their respective diameters. The ratio of their radii is given by

What are the first ionization potentials $(eV)$ of $Be$ and $Ba$ respectively?