Inorganic reactions

Question 1

what color is [Co(H2O)62+]

Answer 1

pink solution

Question 2

what color is [Cr(H2O)6]3+

Answer 2

violet solution

Question 3

Lewis acid

Answer 3

A Lewis acid is a species which can bond by accepting a lone pair of electrons.
Metal cations behave as Lewis acids when they form coordinate bonds with ligands.

Question 4

Lewis base

Answer 4

A Lewis base is a species which can bond by donating a lone pair of electrons.
Ligands behave as Lewis bases when they form coordinate bonds with metal cations.

Question 5

[Fe(H2O)6]2+

Answer 5

pale green

Question 6

[Co(H2O)6]2+

Answer 6

pink

Question 7

[Cu(H2O)6]2+

Answer 7

pale blue

Question 8

[Al(H2O)6]3+

Answer 8

colourless

Question 9

[Cr(H2O)6]3+

Answer 9

pale green

Question 10

[Fe(H2O)6]3+

Answer 10

yellow

Question 11

deprotonation.

Answer 11

Deprotonation is the loss of a proton by a water ligand to form a hydroxo ligand

Cations in aqueous solution are stabilised by the presence of aqua ligands, since the charge on the ion is distributed over a larger area and the polarising power is thus reduced.

If the charge density of the cation is particularly high, the electron density in the aqua ligand moves even closer to the cation and the bonds in the water are weakened. In such cases the hydrogen in the water ligand can be lost as a proton.

Eg [Fe(H2O)6]2+ == [Fe(H2O)5OH]+ + H+

Deprotonation is caused by the high charge density on the central cation, which weakens the O-H bonds in the water ligands, and enables the H+ ( the proton) to leave.

The proton which is lost is given to a base. This can be water, hydroxide ions or ammonia. The extent to which deprotonation takes place depends on the strength of the base.