According to Bohr's atomic theory :

(A) Kinetic energy of electron is $$ \propto {{{Z^2}} \over {{n^2}}}$$.

(B) The product of velocity (v) of electron and principal quantum number (n), $$'vn' \propto {Z^2}$$.

(C) Frequency of revolution of electron in an orbit is $$ \propto {{{Z^3}} \over {{n^3}}}$$.

(D) Coulombic force of attraction on the electron is $$ \propto {{{Z^3}} \over {{n^4}}}$$.

Choose the most appropriate answer from the options given below :

Which one of the following carbonyl compounds cannot be prepared by addition of water on an alkyne in the presence of HgSO₄ and H₂SO₄?

The correct set from the following in which both pairs are in correct order of melting point is :

What is the correct sequence of reagents used for converting nitrobenzene into m-dibromobenzene?