testing for cations

Question 1

Al 3+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(ppt soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 1

white ppt
dissolves
give a colourless solution

Question 2

Ca 2+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(ppt soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 2

white ppt
insoluble
-

Question 3

Cu 2+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(ppt soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 3

light blue ppt
insoluble
-

Question 4

Fe 2+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(ppt soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 4

green ppt
insoluble
-

Question 5

Fe 3+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(ppt soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 5

red(dish)-brown ppt
insoluble
-

Question 6

Zn 2+ reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 6

white ppl formed
dissolves
colourless solution

Question 7

NH4 + reaction w NaOH (sodium hydroxide)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 7

no ppt
ammonia gas produced when warming

Question 8

Al 3+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 8

white ppt
insoluble

Question 9

Ca 2+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 9

NO VISIBLE CHANGE –> no ppt

Question 10

Cu 2+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 10

light blue ppt
soluble
form a dark blue solution

Question 11

Fe 2+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 11

green ppt
insoluble

Question 12

Fe 3+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 12

red(dish)-brown ppt
insoluble

Question 13

Zn 2+ reaction w NH3 - (aq. ammonia)
(ppt formed? If yes, what colour?)
(soluble anot? – can dissolve?)
(if soluble, what is the colour of the solution now?)

Answer 13

white ppt
dissolves
colourless solution