QA Cations

Question 1

Aluminium (AL3+)
NaOH (aq) :
NH3 (aq) :

Answer 1

NaOH (aq) : white ppt, soluble in excess giving colourless soln
NH3 (aq) : white ppt, insoluble in excess

Question 2

Ammonium (NH4+)
NaOH (aq) :
NH3 (aq) :

Answer 2

NaOH (aq) : ammonia produced on warming

NH3 (aq) : -

Question 3

Calcium (Ca2+)
NaOH (aq) :
NH3 (aq) :

Answer 3

NaOH (aq) : white ppt, insoluble in excess

NH3 (aq) : no ppt

Question 4

Copper(II) (Cu2+)
NaOH (aq) :
NH3 (aq) :

Answer 4

NaOH (aq) : Light blue ppt, insoluble in excess

NH3 (aq) : light blue ppt, soluble in excess giving dark blue soln

Question 5

Iron (II) (Fe2+)
NaOH (aq) :
NH3 (aq) :

Answer 5

NaOH (aq) : green ppt, insoluble in excess

NH3 (aq) : green ppt, insoluble in excess

Question 6

Iron (III) (Fe3+)
NaOH (aq) :
NH3 (aq) :

Answer 6

NaOH (aq) : red-brown ppt, insoluble in excess

NH3 (aq) : red-brown ppt, insoluble in excess

Question 7

Lead (II) (Pb2+)
NaOH (aq) :
NH3 (aq) :

Answer 7

NaOH (aq) : white ppt, soluble in excess giving colourless soln
NH3 (aq) : white ppt, insoluble in excess

Question 8

Zinc (Zn2+)
NaOH (aq) :
NH3 (aq) :

Answer 8

NaOH (aq) : white ppt, soluble in excess giving colourless soln
NH3 (aq) : white ppt, soluble in excess giving colourless soln

Question 9

How can Pb2+ be distinguished from Al3+

Answer 9

insolubility of lead (II) iodide or lead (II) chloride