Among the following four aromatic compounds, which one will have the lowest melting point ?

The pair of metal ions that can give a spin only magnetic moment of 3.9 BM for the complex [M(H₂O)₆]Cl₂, is -

The element with Z = 120 (not yet discovered) will be an/a -

What is the work function of the metal if the light of wavelength 4000$$\mathop A\limits^ \circ $$ generates photoelectrons of velocity 6 $$ \times $$ 10⁵ ms^–1 from it ?
(Mass of electron = 9 $$ \times $$ 10^–31 kg;
Velocity of light = 3 $$ \times $$ 10⁸ ms^$$-$$1
Plank's constant = 6.626 $$ \times $$ 10^–34 Js;
Charge of electron = 1.6 $$ \times $$10^–19 JeV^–1)