Which of the following is a chemical property of ammonium salts?

• A. They conduct electricity in solid form.
• B. They are always insoluble in water.
• C. They react with acids to produce hydrogen gas.
• D. They release ammonia gas when heated with a strong base.

Answer: (D)

Verified step by step guidance

1. Understand the difference between physical and chemical properties: Physical properties can be observed without changing the substance's identity, while chemical properties describe how a substance reacts to form new substances.
2. Analyze each option to determine if it describes a chemical property of ammonium salts:
3. Option 1: 'They conduct electricity in solid form' refers to electrical conductivity, which is a physical property, not a chemical property.
4. Option 2: 'They are always insoluble in water' relates to solubility, a physical property, so this is not a chemical property.
5. Option 3: 'They react with acids to produce hydrogen gas' is incorrect because ammonium salts typically do not produce hydrogen gas when reacting with acids; this is not a typical chemical property of ammonium salts.
6. Option 4: 'They release ammonia gas when heated with a strong base' describes a chemical reaction where ammonium salts decompose to release ammonia gas, which is a chemical property.