The angular shape of ozone molecule $(O_3)$ consists of

The number of molecules from the following which contain only two lone pairs of electrons is $........$.
$H_2O, N_2, CO, XeF_4, NH_3, NO, CO_2, F_2$

Which of the following statements is not true?

Which of the following is not a Lewis acid?

Fill in the blanks given below:
$(i)$ The two theories based on the principles of quantum mechanics are ........ and ......... .
$(ii)$ The electronic configuration of carbon in the excited state is ........... .
$(iii)$ Through the combination of atomic orbitals,....... are formed.
$(iv)$ The ${\rm{CH}}_4$ molecule has a .......... shape.

Arrange the following in the decreasing order of their bond enthalpy: $H_2, O_2, N_2$.