PAG 4

Question 1

Halide Test

Answer 1

Add nitric acid
Add silver nitrate dropwise

Cl- =white ppt
Br- =cream ppt
I- = yellow ppt

Hard to distinguish so:
dilute ammonia –> Cl- would dissolve
concentrated ammonia-> Br- would dissolve
silver iodide is insoluble

X- (aq) + Ag+ (aq) ——> AgX (s)

Question 2

Ammonium ion test

Answer 2

Add NaOH (aq) and warm gently

Damp red litmus paper will turn blue (as ammonia is a weak base)

NH4+ (aq) + OH- (aq) —–> NH3 (g) + H2O (l)

Question 3

Carbonate ion test

Answer 3

Add nitric acid

Observe effervescence (CO2 produced)

Test for CO2 with limewater, turns cloudy

CO3 2- (aq) + 2H+ (aq) ——-> CO2 (g) +H2O (l)

Question 4

Sulfate ion test

Answer 4

Add nitric acid
Add barium chloride

white ppt forms

SO4 2- (aq) + Ba2+ (aq) ——-> BaSO4(s)

Question 5

How to do the test’s order?

Answer 5

CaSH