Assertion (A): Ammonia solution is an alkali.
Reason (R ): Ammonia solution turns blue litmus paper red.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is NOT the correct explanation of A.
C. A is true but R is false.
D. A is false and R is True.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states: "Ammonia solution is an alkali."

- **Explanation**: An alkali is a type of base that is soluble in water. Ammonia (NH₃) when dissolved in water forms ammonium hydroxide (NH₄OH), which is indeed a base. Therefore, this statement is **true**.

### Step 2: Understand the Reason
The reason states: "Ammonia solution turns blue litmus paper red."

- **Explanation**: Litmus paper is used to test the acidity or basicity of a solution. Bases turn red litmus paper blue. Since ammonia solution is a base, it will turn red litmus paper blue, not the other way around. Therefore, this statement is **false**.

### Step 3: Conclusion
Now that we have analyzed both the assertion and the reason, we can conclude:

- The assertion is **true**.
- The reason is **false**.

### Final Answer
The correct option is: **Assertion is true but reason is false**.

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