Question

Q7. A few drops of phenolphthalein indicator were added to an unknown
solution A. It acquired pink colour. Now another unknown solution B
was added to it drop by Drop and the solution becomes colorless.
Predict the nature of A & B.​

Answer 1

Answer:

A is base and

B is acidic

Explanation:

Acid + Base → Salt + Water

Phenolphthalein, being a chemical indicator, giver pink colour in basic solutions and gets colourless in acidic solutions. Upon the addition of HCl to the NaOH solution leads to the reaction of neutralisation,

NaOH+HCl→NaCl+H2O

But upon addition of excess of HCl makes the solution acidic hence, the solution gets colourless at the end of the experiment.

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