Correct Option
The correct option is (b).
Explanation
Indicators are substances that exhibit a change in color when brought in contact with acidic or basic solutions. Litmus and turmeric are common natural indicators used to identify the chemical nature of substances based on specific color transitions.
Statement-wise Analysis
- Statement 1 is Incorrect. Lemon juice contains citric acid, making it acidic in nature. Acids turn blue litmus red. They do not change the color of red litmus paper (it remains red). Therefore, lemon juice does not turn red litmus blue.
- Statement 2 is Correct. Soap solution is basic (alkaline) in nature. Bases turn red litmus blue. Consequently, soap solution will change the color of red litmus paper to blue.
- Statement 3 is Incorrect. Milk of magnesia contains magnesium hydroxide, which is a base. Turmeric paste or paper is naturally yellow. In basic solutions, turmeric changes color from yellow to reddish-brown. It does not turn blue.
Key Takeaway
Litmus: Acids turn blue litmus red; Bases turn red litmus blue.
Turmeric: Remains yellow in acidic and neutral solutions; turns reddish-brown in basic solutions.