Grade 12Inorganic Chemistry

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

SRIKANTH A

13 Years agoGrade 12

16 Answers

Srikanth Neeli

13 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

13 Years ago

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

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Srikanth Neeli

13 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

13 Years ago

Shakti Prateek

13 Years ago

this is becoz cu+2 ions r blue in color

SUNAYANA GHOSE

12 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

11 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

10 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

10 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

9 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

9 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

9 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

8 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

7 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

6 Years ago

Dear Student,
Please find below the solution to your problem.

Hydrated copper sulphate CuSO4⋅5H2O 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

5 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