Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
pH and indicators
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →State the colour change observed when litmus paper is placed in (a) an acidic solution and (b) an alkaline solution.
(a)[1 mark]Colour of litmus paper in an acidic solution:
(b)[1 mark]Colour of litmus paper in an alkaline solution:
Question 2
4 marks · Normal
Answer and see the solution →The table below shows the pH values of four different aqueous solutions.
Solution pH P 2 Q 5 R 8 S 13 (a)[1 mark]State which solution is strongly acidic.
(b)[1 mark]State which solution is neutral.
(c)[1 mark]State which solution is weakly alkaline.
(d)[1 mark]State which solution is strongly alkaline.
Question 3
3 marks · Normal
Answer and see the solution →A student adds methyl orange to a solution. The solution turns yellow. They mix the solution with just enough acid to make the colour just change to red.
Estimate the change in pH that the student has achieved. State your reasoning.
Question 4
3 marks · Normal
Answer and see the solution →Explain why a solution with pH 6 is described as weakly acidic and how you could confirm this using an indicator.
Question 5
4 marks · Normal
Answer and see the solution →The table shows the effect of three indicators in different solutions.
Solution Litmus Methyl orange Phenolphthalein Vinegar red red colourless Soapy water blue yellow pink (a)[2 marks]State which solution is acidic. Explain your answer using the indicator results.
(b)[2 marks]State which solution is alkaline. Explain your answer using the indicator results.
Question 6
1 mark · Normal
Answer and check →Which pH value shows a strongly alkaline solution?
- A.pH 2
- B.pH 6
- C.pH 9
- D.pH 13
Question 7
2 marks · Normal
Answer and see the solution →Name two indicators that can distinguish between an acid and an alkali, and state the colour each shows in an alkali.
Question 8
4 marks · Normal
Answer and see the solution →A teacher gives three solutions: X with pH 3, Y with pH 7, and Z with pH 12.
(a)[3 marks]Classify each solution as acidic, neutral, or alkaline.
(b)[1 mark]State which solution is strongly acidic and which is strongly alkaline.