C3 Test for Positive Ions AND Negative Ions :D

Explaining the different tests for positive ions and negative ions XD


Test for Positive Ions

When heated the following metals give off different colours :)

  • Sodium = YELLOW
  • Potassium = PURPLE
  • Calcium = RED
  • Copper = BLUEY GREEN

When adding sodium hydroxide the colours of the metals change (Annoying i know, but still they do O_o)

  • Calcium + Sodium Hydroxide = WHITE precipitate
  • Copper (II) + Sodium Hydroxide = BLUE precipitate
  • Iron (II) + Sodium Hydroxide = SLUDGY GREEN precipitate
  • Iron (III) + Sodium Hydroxide = REDDISH BROWN precipitate
  • Aluminium + Sodium Hydroxide = White at first but then turn COLOURLESS

Ionic Equations just show the stuff we need to know and don't show the tag along things that we don't need to know :D

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Test for Negative Ions

Ok so basically we have learnt the Positive test ions and now we need to know the negative ions O_o i know bit of a drag but god says we do so we gotta learn it :)

Sorry about the numbers not being subscript computers not clever enough for that. :/

  • Hydrochloric Acid can detect Carbonate and Sulphites
  • Carbonates give off CO2 when added to Hydrochloric Acid
  • Sulphites give off SO2 with HCl

You can test for Sulpur dioxide by using Potassium Dichromate (VI) paper

I'm sure your wondering what the hell it is to be honest i don't but we need to know it :(

The paper turns from Orange to Green

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More Negative Ions

More negative ion stuff sorry :(

We are now going to test for Sulphates with Hydrochloric acid and Barium Chloride

  • Sulphate ions produce a white precipitate
  • To test for Sulphate ions add dilute HCL followed by Barium Chloride
  • If the solutions turns white then it means the original compounds was a sulphate

Tests for Halides (Cl-, Br-, I- ) with Nitric Acid and Silver Nitrate

Soo basically you start off with one of them halides and add dilute nitric acid and then Silver nitrate :)

If you start with Cl- you get a WHITE precipitate of SILVER CHLORIDE

If you start with Br- you get a CREAM precipitate of SILVER BROMIDE

And finally if you start with I- you get a YELLOW precipitate of SILVER IODIDE

Well thats all the tests for Positive and Negative Ions, learn it god says we need to, and i'll be doing the C3 test with you Good Luck !! :D

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great thanks

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