Which of the following compounds would have an increase in solubility when placed into an acidic solution? 
a) CaBr₂                                    b) NaI                           c) KCN                         d) LiNO₃                        e) Hg₂Br₂

• A. CaBr₂
• B. NaI
• C. KCN
• D. LiNO₃
• E. Hg₂Br₂

Answer: (C)

Verified step by step guidance

1. Identify the nature of the anions in each compound. Compounds that contain anions which can react with H+ ions from an acidic solution may have increased solubility.
2. Consider the solubility rules and the behavior of each anion in acidic conditions. For example, anions that form weak acids upon reaction with H+ will increase solubility.
3. Examine each compound: CaBr2, NaI, KCN, LiNO3, and Hg2Br2. Determine if the anion can react with H+ to form a weak acid.
4. Focus on KCN: The CN- ion can react with H+ to form HCN, a weak acid, which increases the solubility of KCN in acidic solutions.
5. Conclude that KCN is the compound whose solubility increases in an acidic solution due to the formation of HCN from CN-.