Give reasons for the following :
(i) Covalent bonds are directional bonds while ionic bonds are nondirectional.
(ii) The water molecule has a bent structure whereas carbon dioxide molecule is linear.
(iii) Ethyne molecule is linear.
(i) A covalent bond is formed by the overlapping of atomic orbitals. The direction of overlapping gives the direction of the bond.
(ii) In a water molecule, the oxygen atom is sp3 hybridized and has two lone pairs of electrons.
(iii) In the ethyne molecule, both the carbon atoms are sp hybridized. The two sp hybrid orbitals of both the carbon atoms are oriented in the opposite direction forming an angle of 180°.