Which of the following substances is a weak electrolyte?

• A. LiBr
• B. NH_3
• C. HF
• D. HNO_3

Answer: (C)

Verified step by step guidance

1. Understand what an electrolyte is: an electrolyte is a substance that produces ions and conducts electricity when dissolved in water.
2. Recall that strong electrolytes completely dissociate into ions in solution, while weak electrolytes only partially dissociate.
3. Analyze each substance: LiBr is an ionic compound and a strong electrolyte because it dissociates fully into Li⁺ and Br⁻ ions.
4. NH₃ (ammonia) is a weak base and does not ionize significantly in water, so it is a very weak electrolyte or nonelectrolyte.
5. HF (hydrofluoric acid) is a weak acid, meaning it partially ionizes in water, making it a weak electrolyte, unlike HNO₃ which is a strong acid and strong electrolyte.