Which term refers to the ability of a substance to resist decomposition due to temperature?

• A. Viscosity
• B. Thermal stability
• C. Hydrolytic stability
• D. Mechanical strength

Answer: (B)

Thermal stability is the ability of a substance to resist decomposition when exposed to elevated temperatures. It describes how well a material holds together and maintains its chemical structure as heat increases, without breaking down or reacting to form unwanted products. This is different from viscosity, which is about how thick or flow-resistant a liquid is and changes with temperature; hydrolytic stability, which concerns resistance to reaction with water, not heat alone; and mechanical strength, which measures how much force a material can endure. Materials with high thermal stability will remain intact at higher temperatures until their decomposition point is reached, while less stable ones begin to decompose or transform sooner.