Question

A Solution turns blue Litmus red, its pH is likely to be :

• A. 11
• B. 14
• C. 5
• D. 10

Hint:

"Acids turn blue litmus RED, Bases turn red litmus BLUE." Remember the mnemonic: "Acid-Red" or "BAR" (Blue to Acid to Red). A pH value below 7 confirms acidity.

Answer 1

The Correct Option is C

Step 1: Understand the litmus paper test and pH scale.
Litmus paper is a common indicator used to test the acidity or alkalinity of a solution.
Acids turn blue litmus paper red.
Bases (alkaline solutions) turn red litmus paper blue.
Neutral solutions do not change the color of either red or blue litmus paper. The pH scale ranges from 0 to 14:
pH \(<\) 7 indicates an acidic solution.
pH = 7 indicates a neutral solution.
pH \(>\) 7 indicates a basic (alkaline) solution. Step 2: Apply the litmus test result to determine the nature of the solution.
The problem states that "A Solution turns blue Litmus red". This indicates that the solution is acidic. Step 3: Use the pH scale to find a likely pH value for an acidic solution.
Since the solution is acidic, its pH must be less than 7. Step 4: Evaluate the given options.

(1) 11: This pH is greater than 7, indicating a basic solution. A basic solution would turn red litmus blue, not blue litmus red.
(2) 14: This pH is strongly basic. A strongly basic solution would turn red litmus blue.
(3) 5: This pH is less than 7, indicating an acidic solution. An acidic solution would turn blue litmus red. This is a likely pH.
(4) 10: This pH is greater than 7, indicating a basic solution. Step 5: Conclude the likely pH.
Based on the litmus test, the solution is acidic, and among the given options, pH 5 is the only value that corresponds to an acidic solution. (3) 5