Correct Answer - Option 4 : 10 cc of water at 20°C is mixed with 10 cc of sulphuric acid at 20°C
Concept:
Zeroth Law of thermodynamics:
- The zeroth law of thermodynamics states that if two bodies are each in thermal equilibrium with a third one, then they are in thermal equilibrium with each other.
- Systems are said to be in thermal equilibrium if there is no heat transfer, even if they are in a position to transfer heat, based on other factors.
Explanation:
Option 1
50 cc of water at 25°C is mixed with 150 cc of water at 25°C
Water with different quantities (50 cc and 150 cc) are in thermal equilibrium (At 25°C), Hence the zeroth law of thermodynamics will be applicable.
Option 2
500 cc of milk at 15°C is mixed with 100 cc of water at 15°C
Milk and water at 15°C are at thermal equilibrium. Hence the zeroth law of thermodynamics will be applicable.
Option 3
5 kg of wet stream at 100°C is mixed with 50 kg of dry and saturated steam at 100°C
wet steam and dry and saturated steam are at 100°C. They form a pure substance and don't participate in the reaction. Hence they are in thermal equilibrium.
Option 4
In 10 cc of water at 20°C is mixed with 10 cc of sulphuric acid at 20°C there is no thermal equilibrium between the components of the mixture because there will be a spontaneous ionic reaction which highly exothermic in nature.
