A student makes copper sulfate crystals by adding an excess of copper oxide to dilute sulfuric acid, filtering, and then crystallising the filtrate.
The student wants to make sodium sulfate crystals from sodium hydroxide solution and dilute sulfuric acid.
Why can the student not use the same method of adding an excess of sodium hydroxide and filtering?
Sodium hydroxide is soluble, so the excess cannot be removed by filtering and would be left in the salt.
Sodium hydroxide does not react with dilute sulfuric acid unless the mixture is heated.
Sodium sulfate is insoluble, so it would be removed with the excess sodium hydroxide when the mixture is filtered.
Sodium hydroxide is a base but not an alkali, so it cannot neutralise the acid.
53 exam-style questions on OCR GCSE Chemistry 3.3 Types of chemical reactions, covering 3.3.1 Oxidation and reduction in terms of oxygen, 3.3.2 Acids, alkalis and neutralisation, 3.3.3 The pH scale and measuring pH, 3.3.4 Oxidation and reduction in terms of electrons, 3.3.5 Dilute and concentrated, weak and strong acids, and 3.3.6 Hydrogen ion concentration and pH. Each one has a worked solution and a mark scheme showing where the marks go.