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SingaporeChemistryQuick questions
Experimental Chemistry and Separation Techniques
Quick questions on Identification of ions and gases explained: O-Level Chemistry
6short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is cation tests with sodium hydroxide?Show answer
Adding sodium hydroxide solution to a solution of a metal salt forms a metal hydroxide precipitate whose colour, and whether it dissolves in excess alkali, identifies the cation:
What is cation tests with aqueous ammonia?Show answer
Aqueous ammonia distinguishes the white precipitates that sodium hydroxide cannot:
What are gas tests?Show answer
Forgetting to add acid before the sulfate or chloride test. Dilute nitric acid removes carbonate ions that would otherwise give a false precipitate.
What is q1?Show answer
State the test and result that identifies hydrogen gas. [2 marks]
What is q2?Show answer
A solution gives a red-brown precipitate with sodium hydroxide. Identify the cation. [1 mark]
What is q3?Show answer
Describe how you would distinguish a solution containing chloride ions from one containing iodide ions. [3 marks]
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