ION TESTS

Question 1

SO4 3-

Answer 1

Acidify with dilute HCl
Add BaCl2

Positive result= white precip of BaSO4

Question 2

CO3 2-

Answer 2

Add dilute HCl

Positive result= CO2 will be produced. Bubble through limewater and it will turn cloudy

Question 3

OH-

Answer 3

Damp red litmus paper

Positive result= red to blue

Question 4

Halide ions?

Answer 4

Acidify with dilute HNO3
Add AgNO3
(Add dilute NH3 followed by conc. NH3)

Positive result=
Cl - white p. Dissolves in dilute NH3
Br - cream p. Dissolves in conc. NH3
I - yellow p. Insoluble in conc NH3

Question 5

Mg 2+

Answer 5

In separate test tubes,
Add dilute NaOH positive result= white p
Add dilute H2SO4= no visible change

Question 6

Ca 3+

Answer 6

Flame test produces brick red flame

In separate test tubes,
Add dilute NaOH= white suspension
Add dilute H2SO4= slight white p

Question 7

Sr 2+

Answer 7

Flame test produces red flame

In separate test tubes,
Add dilute NaOH= no visible change
Add dilute H2SO4= white p

Question 8

Ba 3+

Answer 8

Flame test produces green flame

Separately
Add dilute NaOH= no visible change
Add H2SO4= white p

Question 9

NH4 +

Answer 9

Add NaOH
Heat sample
Hold damp red litmus paper at the test tube mouth.

Positive result= red to blue