RP11 - Identifying transition metal ions

Question 1

How do transition metals undergo precipitation reactions?

Answer 1

They react with hydroxide ions to form a
metal hydroxide precipitate.
I.e. Cu2+(aq) + 2OH-(aq) → Cu(OH)2(s)

Question 2

What can be reacted with transition metals for a

precipitation reaction to occur?

Answer 2

● Aqueous sodium hydroxide

● Ammonia

Question 3

What is the first test that can be carried out to identify a

transition metal ion?

Answer 3

● Place 10 drops of each solution (Q, R, S) in a test tube. Add NaOH solution
drop-by-drop to each until in excess. Record any observations.
● Stand in a beaker of hot water for 10 minutes.
Q: (i) yellow solution - (NaOH) orange precipitate - (water) no change
R: (i) light blue solution - (NaOH) deep blue precipitate - (water) no change
S: (i) pale green solution - (NaOH) grey/green precipitate - (water) no change

Question 4

What is the second test that can be carried out to identify transition metal ions?

Answer 4

● Add about 10 drops of each solution (Q, R, S) into a
different test tube with Na2CO3(aq). Shake and record observations
Q: orange precipitate+ effervescence
R: blue/green precipitate
S: grey/green precipitate

Question 5

What can we conclude about Q, R and S?

Answer 5

● Q - Iron (III) ions
● R - Copper (II) ions
● S - Iron (II) ions