A student collects a colourless gas in a test tube. The student holds a lit splint in the gas and the splint goes out.
The student concludes that the gas is carbon dioxide.
Which evaluation of the student's conclusion is correct?
The conclusion is valid, because only carbon dioxide puts out a lit splint.
The conclusion is not valid, because other gases also put out a lit splint. The gas should be bubbled through limewater.
The conclusion is not valid, because carbon dioxide gives a squeaky pop with a lit splint.
The conclusion is valid, because the gas is colourless, so it cannot be chlorine.
52 exam-style questions on OCR GCSE Chemistry 4.2 Identifying the products of chemical reactions, covering 4.2.1 Tests to identify gases, 4.2.2 Tests for aqueous ions and flame tests, and 4.2.3 Instrumental methods of analysis. Each one has a worked solution and a mark scheme showing where the marks go.