Qualitative tests- tests for aqueous cations

Question 1

effect of aqueous sodium hydroxide:ammonia produced on warming.
effect of aqueous ammonia: none.

Answer 1

ammonium (NH4+)

Question 2

• effect of aqueous sodium hydroxide: white ppt., insoluble in excess.
• effect of aqueous ammonia: no ppt., or very slight white ppt.

Answer 2

calcium (Ca2+)

Question 3

• effect of aqueous sodium hydroxide: light blue ppt., insoluble in excess.
• effect of aqueous ammonia: light blue ppt., soluble in excess, giving a dark blue solution.

Answer 3

copper (Cu2+)

Question 4

• effect of aqueous sodium hydroxide: green ppt., insoluble in excess.
• effect of aqueous ammonia: green ppt., insoluble in excess.

Answer 4

iron(II) (Fe2+)

Question 5

• effect of aqueous sodium hydroxide:red-brown ppt., insoluble in excess.
• effect of aqueous ammonia: red-brown ppt., insoluble in excess.

Answer 5

iron(III) (Fe3+)

Question 6

• effect of aqueous sodium hydroxide: white ppt., soluble in excess giving a colourless solution.
• effect of aqueous ammonia: white ppt., soluble in excess, giving a colourless solution.

Answer 6

zinc (Zn2+)