Hypobromous acid (K_a = 2.8 × 10⁻⁹) and hydrocyanic acid (K_a = 4.9 × 10⁻¹⁰) are both weak acids. Determine if reactants or products are favored in the following reaction.
HBrO (aq) + CN⁻ (aq) ⇌ BrO⁻ (aq) + HCN (aq)

• A. reactants
• B. products
• C. both directions are favored equally
• D. neither direction is favored

Answer: (B)

Verified step by step guidance

1. Identify the acids and their conjugate bases in the reaction: HBrO is the acid on the left side, and HCN is the acid on the right side. CN⁻ and BrO⁻ are their respective conjugate bases.
2. Write the equilibrium expression for the acid-base reaction, which involves the transfer of a proton from HBrO to CN⁻, forming BrO⁻ and HCN.
3. Compare the acid strengths by looking at their acid dissociation constants (K_a): HBrO has K_a = 2.8 × 10^{-9} and HCN has K_a = 4.9 × 10^{-10}. The acid with the larger K_a is stronger.
4. Since HBrO is the stronger acid (larger K_a), the equilibrium will favor the formation of the weaker acid and its conjugate base, meaning the products (BrO⁻ and HCN) are favored.
5. Conclude that the equilibrium lies toward the products side because the reaction proceeds from the stronger acid and base to the weaker acid and base.