Wow many pairs of electrons are shared in the
following types of covalent bonds?
a. a single bond
b. a double bond
c. a triple bond

The Explanation is Given below.

Explanation:

Covalent bond:

Covalent bond is formed by mutual sharing of electrons. This mutual sharing of electrons occurs in such a way that each of the combining atom acquires the stable electronic configuration of the nearest noble gas.

a. A single bond :

A single bond is formed when each of the two combining atom share one electron each.

Example: Hydrogen bonding, H - H

b. A double bond :

A double bond is formed when atoms contribute two electrons each.

Example: Oxygen bonding,  O=O

c. A triple bond :

A triple bond is formed on each item contributes three electrons each.

Example: Nitrogen bonding, N≡N

i believe the answer is a.

fe 55.85 g/mol and h2o 18.02 g/mol.