Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Acids, Alkalis and Titrations
83 practice questions
Topics covered
Practice questions
11–20 of 35 · Easy
Question 11
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 12
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 13
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 14
1 mark · Easy
Answer and see the solution →What colour does methyl orange turn in an alkaline solution?
Question 15
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 16
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 17
1 mark · Easy
Answer and see the solution →State the ion responsible for the alkalinity of sodium hydroxide solution.
Question 18
3 marks · Easy
Answer and see the solution →Potassium carbonate ([32mK_2CO_3[0m) can make water alkaline without containing hydroxide ions in its formula.
(a)[1 mark]Write the formula of the ion that makes a solution alkaline.
(b)[2 marks]Explain, using a chemical equation, how potassium carbonate forms an alkaline solution in water.
Question 19
2 marks · Easy
Answer and see the solution →Magnesium hydroxide ([32mMg(OH)_2[0m) is often used as an antacid. It does not dissolve well in water, but any dissolved part is alkaline. Explain why a solution of magnesium hydroxide is alkaline.
Question 20
1 mark · Easy
Answer and see the solution →Name a substance, other than ammonia, that forms an alkaline solution when dissolved in water.