Precipitation reactions
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/8
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai | Chat |
|---|
No analytics yet
Send a link to your students to track their progress
9 Terms
What are precipitation reactions
Occurs when two aqueous solutions containing ions react to form an insoluble ionic solid, called a precipitate
Precipitation colours
What happens when CoCl2, dissolves in water
A pale pink solution forms containing six co-ordinate complex ion [Co(H2O)6]2+
When [Co(H2O)6]2+ with excess HCl blue complex ion [CoCl4]2- forms
When [Co(H2O)6]2+ with NaOH blue green solid Co(OH)2
How do Cu2+ ions react with NaOH
Blue solution reacts to form to form blue ppt copper (II) hydroxide which is insoluble in excess NaOH
Cu2+(aq) + 2OH⁻(aq) → Cu(OH)2(s)
How do Fe2+ ions react with NaOH
Pale green solution reacts to form a pale green ppt of iron (II) hydroxide which is insoluble in excess NaOH but in air is oxidised to iron (III) and turns brown at its surface
Fe2+(aq) + 2OH⁻(aq) → Fe(OH)2(s)
In air:
Fe(OH)2(s) → Fe(OH)3(s)
How do Fe3+ ions react with NaOH
Pale yellow solution reacts to form an orange brown ppt of iron (III) hydroxide which is insoluble in excess NaOH
Fe3+(aq) + 3OH⁻(aq) → Fe(OH)3(s)
How do Mn2+ ions react with NaOH
Pale pink solution reacts to form a light brown ppt of manganese (II) hydroxide which darkens on standing in air and is insoluble in excess NaOH
Mn2+(aq) + 2OH⁻(aq) → Mn(OH)2(s)
How do Cr3+ ions react with NaOH
Violet solution forms a grey-green ppt of chromium (III) hydroxide, this is soluble in excess NaOH and forms a dark green solution
Cr3+(aq) + 3OH⁻(aq) → Cr(OH)3(s)
Cr(OH)3(s) + 3OH⁻(aq) → [Cr(OH)6]3+(aq)
Transition metals precipitation reactions with ammonia
