Tests

Question 1

How to carry out flame test ?

Answer 1

Dip a nichrome wire loop in conc HCl
Dip in unknown compound
Hold loop in blue part of flame
observe colour

Question 2

Calcium ion (Ca2+)

Answer 2

brick red

Question 3

Strontium (Sr2+)

Answer 3

Red

Question 4

Barium (Ba2+)

Answer 4

pale green

Question 5

How to use NaOH solution to identify group 2 ions ?

Answer 5

add NaOH drop wise to a test tube containing metal ion solution
observe precipitate formed
keep adding NaOH until excess

Question 6

Magnesium (Mg2+)

Answer 6

white precipitate

Question 7

calcium (Ca 2+)

Answer 7

slight white precipitate

Question 8

Strontium (Sr2+)

Answer 8

slight white

Question 9

Barium (Ba2+)

Answer 9

No change

Question 10

How to test for ammonia gas

Answer 10

damp red litmus paper (damp so gas can dissolve)
if ammonia present then will turn blue

Question 11

how to test for ammonium ions

Answer 11

add hydroxide ions (OH-)
will produce ammonia gas and water
add dilute NaOH solution and gently heat
if ammonia is given off then ammonium ions must be present

Question 12

how to test for sulfate ions ?

Answer 12

add dilute HCl and BaCl2 solution
will produce white precipitate of BaSO4