IIT JEE , AIEEE Forum - Chemistry , Inorganic Chemistry

devesh_l2k007

Can anyone give the names and colours of all the ions in quatitaive analysis

( And suggest an alternative to cramming them)

The best ans sure will get salutes

devesh_l2k007

And yes
All the reactions too
Thanx in advance

saarika

u better read those frm ne inorganic text buk. and read it three or four times.thats is the only way to get gud score in inorganic chem

vinyassingh

Transition metal ions and colour

Metal(II) salts

Iron(II)

FeSO4.7H2O

FeSO4 + 7H2O e.g. gentle heating of the solid

green solid white solid

[Fe(H2O)6]2+ + H2O

[Fe(H2O)5(OH)]+ + H3O+ e.g. dissolving salt in water

green soln green soln

[Fe(H2O)5(OH)]+ + H2O

[Fe(H2O)4(OH)2] + H3O+ e.g. adding NH3 or NaOH

green soln white ppt (turns grey-green in air)

Adding CO2-3 ions to solutions of iron(II) ions produces a white precipitate of FeCO3

Cobalt(II)

CoCl2.6H2O

CoCl2 + 6H2O e.g. gentle heating of the solid

red solid blue solid

[Co(H2O)6]2+ + H2O

[Co(H2O)5(OH)]+ + H3O+ e.g. dissolving salt in water

pink soln pink soln

[Co(H2O)5(OH)]+ + H2O

[Co(H2O)4(OH)2] + H3O+ e.g. adding NH3 or NaOH

pink soln blue-green ppt

[Co(H2O)4(OH)2] + 6NH3

[Co(NH3)6]2+ + 4H2O + 2OH- e.g. adding excess NH3

blue-green ppt pale yellow straw-coloured soln (turns dark brown in air)

[Co(H2O)6]2+ + 4Cl

[CoCl4]2- + 6H2O e.g. adding excess conc HCl

pink soln blue soln

Copper(II)

[Cu(H2O)6]2+ + H2O

[Cu(H2O)5(OH)]+ + H3O+ e.g. dissolving salt in water

blue soln blue soln

[Cu(H2O)5(OH)]+ + H2O

[Cu(H2O)4(OH)2] + H3O+ e.g. adding NH3 or NaOH

blue soln l ight blue / turquoise ppt

[Cu(H2O)4(OH)2] + 4NH3

[Cu(NH3)4(H2O)2]2+ + 4H2O e.g. adding excess NH3

light blue ppt Royal blue soln

[Cu(H2O)6]2+ + 4Cl^-

[CuCl4]2- + 6H2O e.g. adding excess conc HCl

blue soln olive-green soln

Adding CO2-3 ions to solutions of copper(II) ions produces a green precipitate of CuCO3.Cu(OH)2

Metal(III) salts

Iron(III)

[Fe(H2O)6]3+ + 3H2O

[Fe(H2O)3(OH)3] + 3H3O+ e.g. adding NH3 or NaOH

pale violet soln brown ppt

Note: [Fe(H2O)3(OH)3] actually exists as Fe2O3.xH2O and forms FeO(OH) ("rust") when dry.

2[Fe(H2O)6]3+ + 3CO2-3

2[Fe(H2O)3(OH)3] + 3CO2 + 3H2O e.g. adding carbonate ions

brown ppt

Note: Fe2(CO3)3 is not formed in solution by adding carbonate solutions.

Chromium (III)

[Cr(H2O)6]3+ + 3H2O

[Cr(H2O)3(OH)3] + 3H3O+ e.g. adding NH3 or NaOH

blue-violet soln green ppt

Note: [Cr(H2O)6]3+ solutions which contain chloride ions or sulphate ions will appear green.

[Cr(H2O)3(OH)3] + 3OH-

[Cr(OH)6]3- + 3H2O e.g. adding excess NaOH

green ppt green soln

[Cr(H2O)3(OH)3] + 3OH-

[Cr(NH3)6]3+ + 3H2O e.g. adding excess NH3

green ppt purple soln

2[Cr(H2O)6]3+ + 3CO2-3

2[Cr(H2O)3(OH)3] + 3CO2 + 3H2O e.g. adding carbonate ions

blue-violet soln green ppt

Note: Cr2(CO3)3 in solution is not formed by adding carbonate solutions.

Aluminium

This is not a transition metal, but is included because its hydroxide is amphoteric like chromium hydroxide, and its chemistry is similar in this respect.

[Al(H2O)6]3+ + 3H2O

[Al(H2O)3(OH)3] + 3H3O+ e.g. adding NH3 or NaOH

colourless soln white ppt

[Al(H2O)3(OH)3] + OH-

[Al(OH)4]- + 2H2O e.g. adding excess NH3 or NaOH

white ppt colourless soln

2[Al(H2O)6]3+ + 3CO2^-3

2[Al(H2O_⁾_⁽OH)3] + 3CO2 + 3H2O e.g. adding carbonate ions

colourless soln white ppt

Note: Al2(CO3)3 in solution is not formed by adding carbonate solutions.

Please rate me!!!!!!!!

arun-rashi

for qualitative analysis good book by mtg written by ram i think you consult it.it is very wast topic so i think you consult properly by book.

devesh_l2k007

ny more ans pls

devesh_l2k007

pls reply ........................................................................................

bhuvana89

the only way to remember the colour of ions is to remember them when u do it practically..

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