Q. Is HCl polar or nonpolar?

To decide whether hydrochloric acid, \( \mathrm{HCl} \), is polar or nonpolar, you should look at the polarity of the bond and the overall molecular shape.

Step 1: Identify the types of bonds in \( \mathrm{HCl} \)

\( \mathrm{HCl} \) consists of two atoms: hydrogen (H) and chlorine (Cl). These two atoms form a single covalent bond.

Step 2: Compare electronegativity values

Chlorine is much more electronegative than hydrogen. This means chlorine pulls electron density toward itself.

Electronegativity (typical values):

• \( \chi(\mathrm{Cl}) \) is about \(3.16\)
• \( \chi(\mathrm{H}) \) is about \(2.20\)

The difference is:

\[
\Delta \chi = \chi(\mathrm{Cl}) – \chi(\mathrm{H}) \approx 3.16 – 2.20 = 0.96
\]

A nonzero electronegativity difference indicates the bond has unequal sharing of electrons.

Step 3: Determine whether the bond is polar

Because the electrons spend more time near chlorine, the bond becomes a polar covalent bond. You can represent this idea with partial charges:

• chlorine has a partial negative charge, \( \delta^- \)
• hydrogen has a partial positive charge, \( \delta^+ \)

Step 4: Decide whether the molecule is polar

\( \mathrm{HCl} \) is a diatomic molecule (it has only two atoms). With only one bond and no geometry that could cancel dipoles, the molecular dipole does not cancel out.

Conclusion

\( \mathrm{HCl} \) is polar.