Question

A test tube contains solution of naoh and phenolphthalein . Why the colour of the solution changes when hcl in added to it

Answer 1

Answer:

Since, phenolphthalein is an artificial indicator, it gives pink colour in a basic solution and remains colourless in neutral and acidic solution. When HCl is added to a solution of NaOH and phenolphthalein, its nature changes because of neutralisation and the resultant solution becomes neutral.