BasePairs-101The conjugate base of HAsO42- is:Question 2Select one:a.H3AsO3b.H2AsO4-c.HAsO42-d.AsO43-e.H2AsO42-

Break Down the Problem

1. Identify the species given in the problem: HAsO₄²⁻.
2. Determine what a conjugate base is: The conjugate base of an acid is formed when the acid donates a proton (H⁺).

Relevant Concepts

1. The species given, HAsO₄²⁻, is an acid in this context.
2. When it donates a proton, it will lose one H⁺ ion, resulting in its conjugate base. Hence, we need to remove one hydrogen ion from HAsO₄²⁻ to find its conjugate base.

Analysis and Detail

1. Starting with HAsO₄²⁻, remove one proton (H⁺): $\text{HAsO₄²⁻} \rightarrow \text{HAsO₄}^{3-} \quad \text{(losing H⁺)}$
2. The resulting species is HAsO₄³⁻, which is not listed among the options. Instead, we consider the direct removal of a proton from HAsO₄²⁻ to form H₂AsO₄⁻.

Verify and Summarize

Reviewing the options provided:

• a. H₃AsO₃ – (not a conjugate base)
• b. H₂AsO₄⁻ – (correct, this is formed by removing one proton)
• c. HAsO₄²⁻ – (this is the acid)
• d. AsO₄³⁻ – (this would be a further deprotonated form)
• e. H₂AsO₄²⁻ – (this is incorrect)

Final Answer

The conjugate base of HAsO₄²⁻ is H₂AsO₄⁻ (option b).