Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Acids, Alkalis and Titrations
83 practice questions
Topics covered
Practice questions
21–30 of 83
Question 21
3 marks · Easy
Answer and see the solution →A student is given a solution and asked to measure its pH using universal indicator.
(a)[2 marks]Describe how the student should use universal indicator solution to estimate the pH of the solution.
(b)[1 mark]Explain how the student can decide on the pH value after adding the indicator.
Question 22
2 marks · Easy
Answer and see the solution →Table 1 shows the colour changes of three common indicators in different solutions.
Table 1: Indicator colours in acid and alkali Indicator Colour in Acid Colour in Alkali Litmus red ? Methyl orange red yellow Phenolphthalein ? pink (a)[2 marks]Complete the table by giving the colour of litmus in alkali and phenolphthalein in acid.
Question 23
2 marks · Easy
Answer and see the solution →Explain why a solution with pH 11 is classified as strongly alkaline rather than weakly alkaline.
Question 24
3 marks · Easy
Answer and see the solution →A student uses universal indicator solution to test three unknown liquids. The results are recorded in Table 2.
Table 2: Universal indicator results Liquid Colour observed A orange B green C purple (a)[1 mark]State the likely pH of liquid B, based on the observed colour.
(b)[1 mark]Suggest the type of solution for liquid C (strong acid, weak acid, neutral, weak alkali, strong alkali).
(c)[1 mark]Describe how the universal indicator is used to obtain this information from the liquids.
Question 25
1 mark · Easy
Answer and see the solution →What colour does methyl orange turn in an alkaline solution?
Question 26
3 marks · Easy
Answer and see the solution →The table shows five solutions and their pH values.
Table 3: Solutions and their pH values Solution pH P 3 Q 6 R 7 S 9 T 13 (a)[1 mark]Identify which solution is neutral.
(b)[1 mark]State which solution is a weak acid.
(c)[1 mark]Which solution is strongly alkaline? Explain your answer.
Question 27
2 marks · Easy
Answer and see the solution →A universal indicator chart is shown below.
Universal Indicator Colours pH Colour 2 red 5 orange 7 green 10 blue 13 purple A student tests a solution and sees that it turns orange with universal indicator.
(a)[1 mark]Estimate the pH of the solution based on the chart.
(b)[1 mark]Classify the solution as strongly acidic, weakly acidic, neutral, weakly alkaline, or strongly alkaline.
Question 28
2 marks · Normal
Answer and see the solution →Describe how you would use universal indicator to find the pH of a solution.
Question 29
4 marks · Normal
Answer and see the solution →(a)[2 marks]State the colour of each indicator in an acidic solution.
Indicator Colour in Acidic Solution Litmus Methyl orange Phenolphthalein Universal indicator (b)[1 mark]State the colour of phenolphthalein in an alkaline solution.
(c)[1 mark]Name an indicator which is purple in a neutral solution.
Question 30
3 marks · Normal
Answer and see the solution →A solution has a pH of 2.5. State whether this solution is strongly acidic, weakly acidic, neutral, weakly alkaline, or strongly alkaline. Explain your answer using the pH range classifications.