Chapter 24 - Transition Elements

Question 1

what is the colour of Cu2+ in solution?

Answer 1

Pale blue

Question 2

what is the colour of Fe2+ in solution?

Answer 2

pale green

Question 3

what is the colour of Fe3+ in solution?

Answer 3

pale yellow

Question 4

what is the colour of Mn2+ in solution?

Answer 4

Pale pink

Question 5

what is the colour of Cr3+ in solution?

Answer 5

violet

Question 6

what is the colour of the Fe2+ precipitate when reacted with NaOH?

Answer 6

green

Question 7

what is the colour of the Cu2+ precipitate when reacted with NaOH?

Answer 7

pale blue

Question 8

what is the colour of the Fe3+ precipitate when reacted with NaOH?

Answer 8

orange-brown

Question 9

what is the colour of the Mn2+ precipitate when reacted with NaOH?

Answer 9

light-brown

Question 10

what is the colour of the Cr3+ precipitate when reacted with NaOH?

Answer 10

grey-green

Question 11

what is the colour of the Fe2+ precipitate when reacted with NH3 (aq)?

Answer 11

green

Question 12

what is the colour of the Fe3+ precipitate when reacted with NH3 (aq)?

Answer 12

orange-brown

Question 13

what is the colour of the Mn2+ precipitate when reacted with NH3 (aq)?

Answer 13

Light-brown

Question 14

what is the colour of the Cu2+ precipitate when reacted with NH3 (aq)?

Answer 14

pale blue

Question 15

what is the colour of the Cr3+ precipitate when reacted with NH3 (aq)?

Answer 15

green-grey

Question 16

which ions dissolve in excess NaOH? what colour is the solution formed?

Answer 16

Cr3+, dark green

Question 17

which ions dissolve in excess NH3? what colour is the solution formed?

Answer 17

Cr3+, purple

Cu2+, deep blue

Question 18

Write the equation between Cr3+ and NaOH including state symbols

Answer 18

Cr3+ (aq) +3OH- (aq) –> Cr(OH)3 (s)

Question 19

Write the equation between Cr3+ and NH3 including state symbols

Answer 19

Cr3+ (aq) +3OH- (aq) –> Cr(OH)3 (s)

Question 20

Write the overall equation for the reaction between [Cu(H2O)6]2+ with excess NH3. give the colour changes

Answer 20

[Cu(H2O)6]2+ + 4NH3 –> [Cu(H2O)2(NH3)4]2+ + 4H2O

pale blue solution to deep blue solution

Question 21

Write the overall equation for the reaction between [Cu(H2O)6]2+ with conc HCl. give the colour changes

Answer 21

[Cu(H2O)6] + 4Cl- –> [CuCl4]2- + 6H2O

pale blue solution to yellow solution

Question 22

Write the overall equation for the reaction between [Cr(H2O)6]3+ with excess NH3. give the colour changes

Answer 22

[Cr(H2O)6]3+ + 6NH3 –> [Cu(NH3)6]3+ + 6H2O

violet solution to purple solution

Question 23

Write the equation for the reaction of [Cu(H2O)6]2+ with a small amount of NH3 and give the colour changes

Answer 23

[Cu(H2O)6]2+ +2OH- –> [Cu(H2O)4(OH)2] + 2H2O

pale blue solution to pale blue precipitate