Which statements is correct regarding the diagonal relationship between $Be$ and $Al$ ?
I) Both carbides on hydrolysis produces $C{H}_4$ gas.
II) Both $Be$ and $Al$ oxides are amphoteric in nature.
III) In vapour state chlorides of both exist as chloro-bridge dimer having $(3c-4e)$ bonds
IV) Both $Be$ and $Al$ nitrides on hydrolysis give $N{H}_3$ gas.