Question

When two pairs of electrons are shared, bond is.
(a) Single covalent bond
(b) Double covalent bond
(c) Dative bond
(d) Triple bond

Answer 1

Hint: The mutual sharing of electrons between the participating atoms leads to the formation of a covalent bond. The electron pair which involves in the formation of a covalent bond is called a shared pair and bonding pair electrons. During the covalent bond formation, the sharing of electrons occurs to achieve the noble gas electronic configuration.

Complete step by step solution:A covalent bond is formed between the atom of the same elements (\[{H_2},C{l_2}\]and \[{O_2}\])or between the atom of two different elements having almost same electronegativity difference (\[{H_2}O,C{H_4}\]and \[N{H_3}\]).
Atoms share their electron pair to achieve inert noble gas electronic configuration or to gain stability.
The following is the Lewis Dot Structure of the \[CC{l_4}\]molecule, showing the covalent bond formation by sharing electrons between chlorine and a carbon atom. The Lewis Dot Structure also represents that each atom is following the octet rule.

Image: Lewis Dot Structure of the \[CC{l_4}\]molecule.
The covalent bond can be divided into three types based on the sharing of electron pairs.
(1) Single bond: Formed when sharing of only one electron takes place between two atoms.
For e.g., \[HCl\]has a single bond formed by the sharing of a single electron from hydrogen as well as from a chlorine atom.
(2) Double bond: Formed when two pairs of electrons are involved in sharing between two atoms.
For e.g., \[C{O_2}\]have two double bonds formed between carbon and oxygen atom
(3) Triple bond: Formed when three pairs of electrons are involved in sharing between two atoms. For e.g., Dinitrogen (.\[{N_2}\]) consists of a triple bond.

Therefore from the above explanation we can say option (b) will be the correct option:

Note: Compared to ionic compounds covalent compounds have low melting and boiling points.
Covalent compounds are best soluble in non-polar solvents.
Unlike ionic compounds, covalent compounds are considered as directional in nature i.e., they have a proper direction of overlapping.