Transition Element Reactions

Question 1

What does the addition of aqueous ammonia (2NH3) or aqueous sodium hydroxide (2OH-) form?

Answer 1

They both from hydroxide precipitates with the aqueous metal ion:
Cu2+(aq) + 2OH- –> [Cu(OH)2(H2O)4] (s) +H2O(l)
Cu2+(aq) + 2NH3 –> [Cu(OH)2(H2O)4] (s) + 2NH4+

Question 2

Do COPPER hydroxide ions dissolve in excess NaOH or excess ammonia?

Answer 2

Excess ammonia

Question 3

What does copper II hydroxide form when excess ammonia is added?

Answer 3

It forms [Cu(NH3)4(H2O)2] + 4NH3 —> 2H2O + 2OH-

Question 4

What is iron 2 hydroxide insoluble in?

Answer 4

Aqueous excess ammonia and sodium hydroxide

Question 5

What is iron 3 hydroxide insoluble in?

Answer 5

EXcess sodium hydroxide and excess aqueous ammonia

Question 6

What is mangannese 2 hydroxide insolube in?

Answer 6

Excess aqueous ammonia and sodium hydroxide

Question 7

What is Chromium 3 hydroxide soluble in?

Answer 7

Excess sodium hydroxide and ammonia.
Forms [Cr(OH)6]3- = dark green solution