Assertion: In throttling, temperature remains constant.
Reason: Throttling is isothermal.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts related to throttling processes in thermodynamics.

### Step 1: Understand the Throttling Process
The throttling process is a type of adiabatic process where a fluid flows from a region of high pressure to a region of low pressure through a constricted passage, such as a valve or an orifice.

**Hint:** Recall that in a throttling process, the fluid experiences a drop in pressure without any heat exchange with the surroundings.

### Step 2: Analyze the Assertion
The assertion states that "In throttling, temperature remains constant." This is not universally true. While some fluids may experience little to no temperature change during throttling, it is not a definitive characteristic of the process. The temperature can change depending on the specific conditions and properties of the fluid.

**Hint:** Consider the nature of the fluid and its properties when it undergoes throttling. Is it always true that temperature remains constant?

### Step 3: Analyze the Reason
The reason states that "Throttling is isothermal." An isothermal process is one where the temperature remains constant throughout. However, as established, throttling does not guarantee that the temperature remains constant; thus, it is not accurate to classify throttling as an isothermal process.

**Hint:** Reflect on the definitions of isothermal and throttling processes. Can they be the same?

### Step 4: Conclusion
Both the assertion and the reason are incorrect. In a throttling process, the temperature does not necessarily remain constant, and it is not classified as isothermal.

**Final Answer:** Both the assertion and the reason are false.