Chloric Acid (HClO3) Is A Powerful Oxidizer And Almost A Strong Acid. Its Used For Making Chlorate Salts. (A) Regardless Of The Formal Charge, Apply Octet Rule To Suggest Four (04) Possible Lewis Structures Of HClO3 (B) Use Formal Charge To Determine The Most Plausible Lewis Structures Of HClO3 (C) Predict The Approximate Values For Bond Angles
Question 1: Chloric acid (HClO3) is a powerful oxidizer and almost a strong acid. Its used for making chlorate salts.
(a) Regardless of the formal charge, apply octet rule to suggest four (04) possible Lewis structures of HClO3
(b) Use formal charge to determine the most plausible Lewis structures of HClO3
(c) Predict the approximate values for bond angles of HClO3
(d) Use box diagram to present the hybrid orbital of H, Cl and O in HClO3
(e) Indicate electrons that form s and p bonds in the hybrid orbital diagram of each element on in HClO3
The Correct Answer and Explanation is :
(a) Possible Lewis Structures of HClO₃:
- Structure 1:
- The chlorine (Cl) is at the center with single bonds to three oxygens (O). Each oxygen is also bonded to a hydrogen atom (forming an -OH group).
- The chlorine has no lone pairs, and the oxygens have lone pairs to satisfy the octet rule.
- Structure 2:
- The chlorine is in the center, with double bonds to two oxygens and a single bond to the third oxygen, which is bonded to a hydrogen.
- The two oxygens involved in the double bonds each have lone pairs, while the oxygen bonded to hydrogen has lone pairs as well.
- Structure 3:
- The chlorine atom is in the center with a single bond to each of the three oxygens. The oxygen bonded to hydrogen (OH) has lone pairs, and the other two oxygens have double bonds to chlorine, resulting in octets for all atoms.
- Structure 4:
- The chlorine is central, with two oxygens attached by single bonds, and one oxygen attached by a double bond. The oxygen attached to hydrogen is shown with its lone pairs.
(b) Formal Charge and Most Plausible Lewis Structure:
To determine the most plausible Lewis structure, we calculate the formal charge for each atom. Formal charge is calculated using the formula:
[
\text{Formal charge} = \text{Valence electrons} – (\text{Lone electrons} + \frac{\text{Bonding electrons}}{2})
]
After calculating the formal charges for each structure, the structure with the lowest formal charges on all atoms is generally the most stable.
- In Structure 2, chlorine typically has a formal charge of 0, and the oxygens are balanced with formal charges close to 0. This structure is likely the most plausible since formal charges are minimized.
(c) Predicted Bond Angles:
Chloric acid (HClO₃) has a trigonal pyramidal molecular geometry around the chlorine atom, due to the lone pair of electrons on chlorine. The predicted bond angles in HClO₃ would be approximately 107°, similar to the bond angles in other trigonal pyramidal molecules (such as ammonia).
(d) Hybrid Orbital Diagram of H, Cl, and O:
- H (Hydrogen): Has 1s orbital, involved in sigma bonding with oxygen.
- Cl (Chlorine): Has 3s and 3p orbitals. The chlorine atom uses one of its 3p orbitals and one 3s orbital to form hybrid orbitals for bonding.
- O (Oxygen): Each oxygen uses one of its 2p orbitals to hybridize with chlorine’s orbitals.
(e) Electrons in S and P Bonds:
- S Bonds: Electrons involved in single bonds, typically from the s and p orbitals, including those in the H-O bonds.
- P Bonds: Electrons from p orbitals that form double bonds, like in the Cl=O bonds.
This hybridization and bonding result in the molecular structure of HClO₃.