The concentration of a sodium hydroxide solution can be determined by titration with hydrochloric acid of a known concentration.
25.0 cm3 of the sodium hydroxide solution was measured using a pipette and transferred to a conical flask.
A few drops of phenolphthalein indicator were added to the alkali in the conical flask. Hydrochloric acid was added to the flask from a burette until the indicator changed colour.
Describe the colour change seen in the conical flask at the end point of the titration.
Practise Edexcel GCSE Chemistry Acids with exam-style questions for Foundation and Higher tier. 100 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.