Phenolphthalein is pink in an aqueous solution having a ph of (1) 5 (2) 2 (3) 7 (4) 12

Answer : Phenolphthalein is pink in an aqueous solution having a ph of 12.

Explanation :

Phenolphthalein is an acid-base indicator. It is a colorless solution which remains colorless in acidic solution and changes to pink in basic solution.

An acidic solution has a pH of less than 7 whereas a basic solution has a pH of greater than 7.

The pH transition range for phenolphthalein is between 8-10. Than means when the pH is greater than 8, the color of the solution starts to change.

Among the given options, the only option that shows a basic solution is option (4) . Therefore we can say that phenolphthalein would be pink in a solution having a pH of 12.

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