Question

Assertion: Heat and work are "definite quantities"
Reason: Heat and work are not properties of a system; their values depend on the path of the process and vary accordingly.
A. Both Assertion and Reason are individually true and Reason is the correct explanation of Assertion.
B. Both Assertion and Reason are individually true but Reason is not the correct explanation of Assertion.
C. The assertion is true but Reason is false.
D. The assertion is false but Reason is true.

Answer 1

Hint: Thermodynamics is a branch of physics that deals with heat, work, and temperature and their inter-conversion of heat and other forms of energy. The state function refers to temperature, pressure, etc. These are called state functions because these values depend only on the state of the system and not on how it reached that state. And path functions are functions that depend on the path taken to reach the specific value.

Complete step by step solution:
Heat and work are definite quantities. This statement is not true. Because heat and work both are path functions. And path functions are called indefinite properties. These two functions are dependent on how the thermodynamic system changes from the initial to the final state and therefore make it dependent on their path.
Heat and work cannot be called the properties of a system because their values depend on the path of the process and vary accordingly. This statement is true because heat and work, unlike pressure or temperature, are not intrinsic properties of a system. Because we say something is a property of a system, the difference in the properties between one state and another state should always remain constant. And in the case of heat and work, they are path-dependent and therefore change accordingly in the whole process.
Now let us see each option and analyze whether they are true or not.
Option A is not true because it states that both assertion and reason are true and the reason is the correct explanation of assertion. As we said already, the assertion is not true. And also reason does not explain the assertion. Because reason will make a controversial statement over assertion.
Option B is also not true because it states that both assertion and reason are individually true but the reason is not the correct explanation of assertion. Because the assertion itself is not true.
Option C is also not true because it says assertion is true but the reason is false. But it is correct in the opposite way.
Option D is true because it says the assertion is false but the reason is true. And this says exactly as we explained.

Therefore the correct option is D.

Note:
State functions are also called point functions. These are referred to as functions that are dependent only on the properties of the system. They are not dependent on the process which the system undergoes. So to tell whether a property is a state or path function we need to keep in mind which properties are dependent on which function.