Match the type of interaction in column A with the distance dependence of their interaction energy in column B

A	B
(i) ion-ion	(a) $${1 \over r}$$
(ii) dipole-dipole	(b) $${1 \over {{r^2}}}$$
(iii) London dispersion	(c) $${1 \over {{r^3}}}$$
	(d) $${1 \over {{r^6}}}$$

The ratio of the mass percentages of ‘C & H’ and ‘C & O’ of a saturated acyclic organic compound ‘X’ are 4 : 1 and 3 : 4 respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound ‘X’ is ________.

The major product obtained from E₂ - elimination of 3-bromo-2-fluoropentane is

Three elements X, Y and Z are in the 3^rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of X, Y and Z is :