qualitative analysis of ions

Question 1

carbonate test

Answer 1

add dilute nitric acid - neutralisation reaction

bubble the gas through lime water - calcium hydroxide solution

a white ppt forms + lime water turns clpudy

Question 1

what is the white ppt in the carbonate test

Answer 1

calcium carbonate

Question 2

test for sulfates

Answer 2

add barium nitrate

white ppt forms

Question 3

what happens of you add barium chloride

Answer 3

introducing chloride ions - invalidate next test

Question 4

what is the white ppt in the sulfate test

Answer 4

barium sulfate

Question 5

halide test

Answer 5

add aq silver nitrate to aqueous solution of a halide

silver halides forms ppt - different colours

add aq ammonia

Question 6

colours of halide ppt

Answer 6

chloride - white

bromide - cream

iodide - yellow

Question 7

results of ammonia test

Answer 7

chloride - soluble in dilute ammonia

bromide - soluble in conc ammonia

iodide - insoluble

Question 8

sequence of test

Answer 8

carbonate
sulfate
halides

Question 9

why that order

Answer 9

neither halide ions or sulfate ions produce bubbles with dilute acid

Barium sulfate also white ppt - must do carbonate test first

silver carbonate and silver sulfate are also ppt - must do halide test last

Question 10

test for ammonium ion

Answer 10

aq sodium hydroxide added to solution of the ion

ammonia gas is produced

mixture is warmed + ammonia gas is released

smell ammonia

OR

ammonia - alkaline

turn litmus paper blue

Question 11

why unlikely to see ammonia gas bubbles

Answer 11

ammonia is very soluble in water