Assertion (A) Molarity of a solution in liquid state changes with temperature.
Reason (R ) The volume of a solution charges with change in temperature.

Options

A. Assertion and reason both are correct statements and reason is correcft explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion and reason both are incorrect statements.

Explanation

To solve the question regarding the assertion and reason statements, we will analyze both statements step by step.

### Step 1: Understand the Assertion
**Assertion (A)**: Molarity of a solution in liquid state changes with temperature.

- **Definition of Molarity**: Molarity (M) is defined as the number of moles of solute per liter of solution. It is mathematically expressed as:
\[ M = \frac{\text{moles of solute}}{\text{volume of solution in liters}} \]

### Step 2: Analyze the Reason
**Reason (R)**: The volume of a solution changes with change in temperature.

- **Effect of Temperature on Volume**: It is a well-known fact in chemistry that the volume of liquids generally expands when heated and contracts when cooled. Thus, the volume of a solution is indeed affected by temperature changes.

### Step 3: Connect the Assertion and Reason
- Since molarity is dependent on the volume of the solution, any change in volume due to temperature will affect the molarity.
- When the temperature increases, the volume of the solution increases, leading to a decrease in molarity (since molarity is inversely proportional to volume).
- Conversely, when the temperature decreases, the volume of the solution decreases, leading to an increase in molarity.

### Step 4: Conclusion
- Both the assertion and the reason are correct.
- The reason provided (that the volume of the solution changes with temperature) correctly explains why the molarity changes with temperature.

### Final Answer
- Both the assertion (A) and the reason (R) are correct, and the reason is the correct explanation for the assertion.