Question

Identify the most polar bond in each molecule. (a) \(\mathrm{HSCH}_{2} \mathrm{CH}_{2} \mathrm{OH}\) (b) \(\mathrm{CHCl}_{2} \mathrm{~F}\) (c) \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\)

Short answer

Question: In each of the following molecules, identify the most polar bond: (a) HSCH2CH2OH, (b) CHCl2F, and (c) HOCH2CH2NH2. Answer: (a) O-H bond, (b) C-F bond, (c) O-H bond.

Step-by-step solution

(a) Identify the bonds in HSCH2CH2OH

In HSCH2CH2OH, we have the following bonds: H-S, S-C, C-H, C-H, C-O, and O-H.

(a) Determine the electronegativity difference of each bond

Using the electronegativity values for each atom (obtained from a periodic table or a reference), calculate the electronegativity difference for each bond. Electronegativity values: H=2.1, S=2.5, C=2.5, O=3.5 - H-S: |2.1 - 2.5| = 0.4 - S-C: |2.5 - 2.5| = 0 - C-H: |2.5 - 2.1| = 0.4 - C-O: |2.5 - 3.5| = 1.0 - O-H: |3.5 - 2.1| = 1.4

(a) Identify the most polar bond

The bond with the highest electronegativity difference is the O-H bond with a difference of 1.4, making it the most polar bond in the molecule.

(b) Identify the bonds in CHCl2F

In CHCl2F, we have the following bonds: C-H, C-Cl, and C-F.

(b) Determine the electronegativity difference of each bond

Once again, use the electronegativity values for each atom to calculate the electronegativity difference for each bond. Electronegativity values: Cl=3.0, F=4.0 - C-H: |2.5 - 2.1| = 0.4 - C-Cl: |2.5 - 3.0| = 0.5 - C-F: |2.5 - 4.0| = 1.5

(b) Identify the most polar bond

The bond with the highest electronegativity difference is the C-F bond with a difference of 1.5, making it the most polar bond in the molecule.

(c) Identify the bonds in HOCH2CH2NH2

In HOCH2CH2NH2, we have the following bonds: O-H, C-H, C-H, C-O, N-H, and N-H.

(c) Determine the electronegativity difference of each bond

Once again, use the electronegativity values for each atom to calculate the electronegativity difference for each bond. Electronegativity values: N=3.0 - O-H: |3.5 - 2.1| = 1.4 - C-H: |2.5 - 2.1| = 0.4 - C-O: |2.5 - 3.5| = 1.0 - N-H: |3.0 - 2.1| = 0.9

(c) Identify the most polar bond

The bond with the highest electronegativity difference is the O-H bond with a difference of 1.4, making it the most polar bond in the molecule.