Chapter 24 - Reactions of Inorganic Compounds in Aqueous Solutions

Question 1

Are the complexes formed by Fe3+ and Al3+ more or less acidic than those of Cu2+ and Fe2+? Why?

Answer 1

They are more acidic. This is because they have a higher charge, meaning they pull the O closer towards the ion, weakening the O-H bond making it easier to less an H+ ion, increasing acidity of the solution

Question 2

Gives test tube reactions of the 4 ions you need to know with OH- ions

Answer 2

Fe2+ - green ppt
Cu2+ - blue ppt
Fe3+ - brown ppt
Al3+ - white ppt, dissolves in excess

Question 3

Gives test tube reactions of the 4 ions you need to know with CO3(2-) ions

Answer 3

Fe2+ - green ppt, solution of FeCO3
Cu2+ - blue/green ppt, solution of CuCO3
Fe3+ - brown ppt, CO2 released
Al3+ - white ppt, CO2 released

Question 4

Gives test tube reactions of the 4 ions you need to know with NH3

Answer 4

Fe2+ - green ppt
Cu2+ - blue ppt, deep blue solution in excess
Fe3+ - brown ppt
Al3+ - white ppt

Question 5

What colour solution do the 4 complexes you need to know form?

Answer 5

Fe2+ - green solution
Cu2+ - blue solution
Fe3+ - yellow/lilac solution
Al3+ - colourless solution