Question

Which of the following changes are irreversible in nature?

• A. Setting of cement
• B. Melting of candle wax
• C. Dissolution of sugar in water
• D. Woolen yarn to knitted sweater

Answer 1

The correct option is A Setting of cement

The setting of cement is an example of irreversible change as once the process is complete, its chemical properties are altered and it cannot be obtained in its original form. We can obtain the sugar dissolved in a solution by the process of evaporation. Melted wax can be converted to its solid state upon cooling. Woolen yarn also be obtained back in its original form by unfastening the knots in the sweater.