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CuSO4.5H2O is blue in colour while CuSO4 is colourless. Why?

CuSO4.5H2O is blue in colour while CuSO4 is colourless. Why?

Grade:12

16 Answers

Srikanth Neeli
38 Points
11 years ago

Cuso4.5h20 is blue in colour because its oxidation state is +2 thus it has unpaired electrons in it .so d-d transistion is possible so it exhibits colour where in the other complex d-d transistion is not possible thats why it colourless

 

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sanatan sharma
26 Points
11 years ago

it is due to the water absorbed by it , it appears blue in colour 

 

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Srikanth Neeli
38 Points
11 years ago

In case first complex d-d transition is possible but in second complex d-d transition is not possible thats why second complex has no colour

upender surepally
126 Points
11 years ago

Cuso4.5h20 is blue in colour because its oxidation state is +2 thus it has unpaired electrons in it .so d-d transistion is possible so it exhibits colour where in the other complex d-d transistion is not possible thats why it colourless

 

Shakti Prateek
14 Points
11 years ago

this is becoz cu+2 ions r blue in color

SUNAYANA GHOSE
18 Points
10 years ago
CuSO4.5H2O gives [Cu(H2O)4]+2 ion which is blue in colour. That is why CuSO4.5H2O is coloured but CuSO4 is colourless or can be said white due to lack of water molecule. It absorbs moisture and turn blue in colour.
Gaurav jhaa
9 Points
9 years ago
Since aq.CuSO4 contains 5H2O molecules which act as ligand and due to LMCT(Ligand to Metal Charge Transfer) the colour of sloution is blue, it is not due to d-d transition since it is d9 system so there is no any posiblity of d-d transition . For more detail go through J.Huhyee or contact me -
Sagnik Mukherjee
11 Points
8 years ago
In the case of CuSO4 . 5H2O , Cu +2 contains an unpaired electon Cu: [Ar] 4s0 3d9 so paramagnatic in nature and for that reason d-d trasition is possible , due to the d-d transition it exhibits blue colour. But in the case of CuSO4 no d-d transition is observed so it is colourless.
Gaurav jhaa
9 Points
8 years ago
CuS04.5H2O is blue not because of d-d transition but because of charge transfer (LMCT-Ligand To Metal Charge Transfer). And these 5 water of hydration helps in LMCT to be it blue in colour..For more contact ….Gaurav jhaa
Arsalaan
13 Points
7 years ago
CuSO4 .5H2O is blue in colour because when Water is CuSO4 some part of it ionises in it and there by impart colour to it
Idimiyo Gift
13 Points
7 years ago
Copper(II) in CuSO4 has the following electronic configuration [Ar] 4s0 3d9, where d-electron can move within d-level. However, zink(II) in ZnSO4 has completely filled d-level [Ar] 4s0 3d10 with no possibility to move some electrons within that level. In turn, those transfers of the electrons within the d-level are making d-metal cations colored.
satyam singh
19 Points
7 years ago
Anhydrous cuso4 is in white colour and it turns into cuso4.5h2o to absorb water in surrounding and turns into blue colour
Sumeet
19 Points
7 years ago
It is due to d-d transission i.e unpaired electrons movement which results in colour and by observation it`s blue
jehan
13 Points
5 years ago
Its a D block transition metal, with an empty D orbital, therefore forms coordination complexes easily resulting in the absorption of crystalisation of water. The unpaired electron movement in tthe d-d transition is responsible for the blue colour
Rishi Sharma
askIITians Faculty 646 Points
4 years ago
Dear Student,
Please find below the solution to your problem.

Hydrated copper sulphate CuSO4​⋅5H2​O is blue in colour. The ligand (water) molecules causes splitting of d orbitals. This facilitates d-d transition and colour.
Anhydrous copper sulphate CuSO4​ is colourless. In the absence of ligand (water) molecules, splitting of d orbitals is not possible. Hence, d-d transition is not possible.

Thanks and Regards
Saneha
15 Points
3 years ago
In cuso4.5h2o water acts as a ligand so it carries out crystal field splitting due to which d orbital split into two t2g and eg of different energy levels .Therefore d-d transition is possible while in Cuso4 there is no ligand so no splitting hence no colour

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