Saturday 18 May 2013

2.37 describe tests for the cations: i Li+ , Na+ , K+ , Ca2+ using flame tests ii NH4 + , using sodium hydroxide solution and identifying the ammonia evolved iii Cu2+, Fe2+ and Fe3+, using sodium hydroxide solution

Flame tests

Lithium: Red
Potassium: Lilac
Calcium: Brick Red
Sodium: Yellow/orange

Identifying  the ammonium ion

Test: Add aqueous sodium hydroxide to the solid, or solution, under test and warm the mixture.

Result: If ammonium ions are present then a pungent-smelling gas is produced. The gas is produced turns damp red litmus paper blue. 

Identifying metal cations

Copper (II) : blue precipitate
Iron (II): green precipitate
Iron (III): brown precipitate

6 comments:

  1. this is so useful ^_^ Thank youuuu!

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  2. your blog is amazing. What my teacher couldnt teach me in 9 months, you taught me in 28 hours. yes. 28 hours i took to finish the syllabus and tomorrow is my Chemistry 2017 gcse. I hope along with the help of your blog and god, i can pass this test.

    you have been of great help lucy. And i wish you the best in life

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