Chapter 18, Problem 37R

To determine

To Choose: The correct option.

Answer to Problem 37R

The correct option is (A).

Explanation of Solution

Introduction:

A chemical formula is a way to provide knowledge on the chemical quantities of atoms that make up a given chemical substance or molecule. Non-polar molecules are those which don’t have any charge separation. There is no electropositive metal and electropositive nonmetal. They don’t have any partial charges.

${\text{N}}_{\text{2}}$ is a covalent compound with three covalent bonds. As there are 2 nitrogen atoms present, each nitrogen shares the electron present in the outermost shell to complete its octet. There is no charge separation and hence it is a non-polar compound.

$\text{NaCl}$ is having sodium atom and chlorine atom bonded together by an ionic bond. Sodium being more electronegative develops positive charge loses its 1 electron present in outermost shell and chlorine being more electronegative gains 1 electron to complete outermost shell and develops a negative charge. Hence, it is an ionic compound. Therefore, option (C) is not correct.

${\text{H}}_{\text{2}}\text{O}$ is a covalent compound. The water molecule has 2 atoms of hydrogen and one atom of oxygen. Each hydrogen atom has 1 valence electron and they require 1 electron to complete their orbit. Oxygen has 6 electrons in its outer shell and needs 2 electrons to complete its octet. Thus, both hydrogen and oxygen share the electrons with each other and form a polar covalent bond. Hence, option (B) is wrong.

$\text{HCl}$ is also a covalent compound. Hydrogen is electropositive and it has 1 valence electron. Chlorine is electronegative having 7 electrons in its outermost shell. Thus, both hydrogen and chlorine share their electrons and form a polar covalent bond.

Therefore, the correct option is (A).

Conclusion:

Hence, the ${\text{N}}_{\text{2}}$ represents a non-polar molecule.