An experiment is performed to generate a sample of hydrogen chloride gas, which is denser than air, and collect it in a gas jar by downward delivery (upward displacement of air).
Suggest why damp blue litmus paper is placed at the top (mouth) of the gas jar.
Practise Edexcel GCSE Chemistry Acids with exam-style questions for Foundation and Higher tier. 276 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
