Which of the following best describes the polarity of the molecule HBrO (hypobromous acid)?

• A. HBrO is a polar molecule due to the difference in electronegativity between its atoms.
• B. HBrO is ionic and therefore does not have molecular polarity.
• C. HBrO is nonpolar because all the bonds are between atoms of similar electronegativity.
• D. HBrO is a nonpolar molecule because its molecular geometry is symmetrical.

Answer: (A)

Verified step by step guidance

1. Step 1: Identify the atoms in the molecule HBrO and their electronegativities. The molecule consists of hydrogen (H), bromine (Br), and oxygen (O). Oxygen is highly electronegative, bromine is moderately electronegative, and hydrogen is the least electronegative among them.
2. Step 2: Determine the types of bonds present in HBrO. Typically, HBrO has an O-H bond and a Br-O bond. Since oxygen is more electronegative than both hydrogen and bromine, these bonds are polar covalent bonds.
3. Step 3: Analyze the molecular geometry of HBrO. The molecule is not symmetrical because oxygen is bonded to both hydrogen and bromine, which have different electronegativities and sizes, leading to an asymmetrical shape.
4. Step 4: Understand that polarity depends on both bond polarity and molecular geometry. Because the bonds are polar and the molecule is asymmetrical, the dipole moments do not cancel out.
5. Step 5: Conclude that HBrO is a polar molecule due to the difference in electronegativity between its atoms and its asymmetrical molecular geometry, which results in a net dipole moment.