Place the following in order of increasing X-A-X bond angle, where A represents the central atom and X represents the outer atoms in each molecule. HCN H₂O H₃O⁺ A) H₃O⁺

Question

Place the following in order of increasing X-A-X bond angle, where A represents the central atom and X represents the outer atoms in each molecule. HCN H₂O H₃O⁺ A) H₃O⁺ < HCN < H₂O B) H₃O⁺ < H₂O < HCN C) HCN < H₃O⁺ < H₂O D) H₂O < HCN < H₃O⁺ E) H₂O < H₃O⁺ < HCN

Quizplus · Accepted Answer

The X-A-X bond angle is determined by the repulsion between the outer atoms X, which pushes them away from each other and leads to a wider bond angle. In H₂O, the central atom S has two outer atoms (H and O), while in H₃O⁺, it has three outer atoms (H, O, and an extra proton). In HCN, the central atom C has only two outer atoms (H and N). Based on this, we can predict that the X-A-X bond angle will be widest in H₃O⁺ (due to three outer atoms), narrower in H₂O (due to two outer atoms and a lone pair on the sulfur atom), and narrowest in HCN (due to two outer atoms and a small size of the N atom in comparison to S or O). Therefore, the correct order of increasing X-A-X bond angle is H₂O < H₃O⁺ < HCN, which is option E.

Place the Following in Order of Increasing X-A-X Bond Angle