Problem 31 - Chemistry: The Central Science

Question

(a) Does \(\mathrm{SCl}_{2}\) have a dipole moment? If so, in which direction does the net dipole point? (b) Does \(\mathrm{BeCl}_{2}\) have a dipole moment? If so, in which direction does the net dipole point?

Step-by-Step Solution

Answer

(a) Yes, SCl2 has a dipole moment. The net dipole points from the sulfur atom (less electronegative) to the center point between the two chlorine atoms (more electronegative). (b) No, BeCl2 does not have a dipole moment, as the bond dipoles cancel each other out due to its linear molecular structure.

Step 1: Molecular Structure and Polarity of SCl2

The molecule SCl2 (sulfur dichloride) has a central sulfur atom bonded to two chlorine atoms. The sulfur atom has 3 lone pairs and 2 bonding pairs of electrons. The electron pair geometry of SCl2 is trigonal bipyramidal, but because of the presence of only two bonding pairs of electrons, it has a bent molecular geometry. When determining molecular geometry, we only consider the positions of the bonded atoms and ignore the lone pairs. SCl2 molecule has polar S-Cl bonds due to the electronegativity difference between sulfur and chlorine atoms. Since the molecule has a bent shape, the bond dipoles do not cancel each other and there is a net dipole moment.

Step 2: Direction of Dipole Moment in SCl2

The direction of the net dipole moment in SCl2 is from the sulfur atom (less electronegative) to the center point between the two chlorine atoms (more electronegative).

Step 3: Molecular Structure and Polarity of BeCl2

The molecule BeCl2 (beryllium dichloride) consists of a central beryllium atom bonded to two chlorine atoms. The beryllium atom has no lone pairs and 2 bonding pairs of electrons. The electron pair geometry of BeCl2 is linear, and its molecular geometry is also linear since there are no lone pairs on the central atom to distort the shape. BeCl2 molecule has polar Be-Cl bonds due to the electronegativity difference between beryllium and chlorine atoms. However, because of the linear molecular geometry, the bond dipoles cancel each other out.

Step 4: Direction of Dipole Moment in BeCl2

As the bond dipoles cancel each other out in BeCl2, it does not have a net dipole moment. To sum up: - SCl2 has a net dipole moment with its overall direction from the sulfur atom to the center point between the two chlorine atoms. - BeCl2 does not have a net dipole moment due to the cancellation of bond dipoles in its linear molecular structure.