QA

Question 1

excess zn2+ in sodium hydroxide

Answer 1

white precipitate that dissolves to form colourless solution

Question 2

al3+ in excess naOH

Answer 2

white precipitate that dissolves in excess naOH to form a colourless solution

Question 3

ca2+ in excess naOH

Answer 3

white precipitate insoluble in excess naOH

Question 4

cu2+ in excess naOH

Answer 4

light blue precipitate is insoluble in excess naOH

Question 5

fe2+ in excess naOH

Answer 5

green precipitate is insoluble in excess naOH

Question 6

fe3+ in excess naOH

Answer 6

red brown precipitate is insoluble in excess naOH

Question 7

nh4+ with a few drops of naOH

Answer 7

1. No precipitate is formed
2. On heating colourless and pungent gas is produced that turns red litmus paper blue (ammonia gas)

Question 8

nh4+ in excess naOH

Answer 8

no change is observed

Question 9

zn2+ in excess ammonia

Answer 9

white precipitate dissolves in excess ammonia to form a colourless solution

Question 10

al3+ in excess ammonia

Answer 10

white precipitate insoluble in excess ammonia

Question 11

ca2+ with a few drops of ammonia

Answer 11

no precipitate formed

Question 12

cu2+ with excess ammonia

Answer 12

light blue precipitate dissolves in excess ammonia to form a dark blue solution

Question 13

fe2+ in excess ammonia

Answer 13

green precipitate is insoluble in excess ammonia

Question 14

fe3+ in excess ammonia

Answer 14

red brown precipitate is insoluble in excess ammonia

Question 15

test for carbonate ion, and observations

Answer 15

add hydrochloric acid, bubble gas given off into limewater

effervescence observed, colourless odourless gas evolved (co2) which forms a white precipitate when bubbled into limewater.

Question 16

test for sulfate ion and observations

Answer 16

add nitric acid, then add barium nitrate solution

white precipitate is formed

Question 17

test for chloride ion and observations

Answer 17

add dilute nitric acid, then add silver nitrate solution.

white precipitate is formed

Question 18

test for iodide ion

Answer 18

add dilute nitric acid, then add silver nitrate solution

yellow precipitate is formed

Question 19

test for nitrate

Answer 19

add sodium hydroxide, ten add a piece of aluminium oil. warm the mixture and test the gas given off with a piece of moist red litmus paper.

effervescence is observed. colourless and pungent gas evolved (ammonia) which turns moist red litmus paper blue.

Question 20

test for ammonia

Answer 20

place a piece of moist red litmus paper at mouth of test tube

colourless pungent gas evolved turns moist red litmus paper blue

Question 21

ammonia colour/ smell

Answer 21

colourless, pungent gas

Question 22

test for chlorine

Answer 22

place a piece of moist blue litmus at the mouth of the test tube

pale greenish-yellow and pungent gas evolved and moist blue litmus paper turns red and then bleached

Question 23

colour/smell of chlorine

Answer 23

pale greenish/yellow and pungent gas

Question 24

sulfur dioxide test and observation

Answer 24

place a piece of filter paper soaked with acidified potassium manganate (vii) solution at the mouth of the test tube.

colourless and pungent gas turns purple acidified potassium manganate (vii) colourless

Question 25

appearance of sulfur dioxide

Answer 25

colourless and pungent gas

Question 26

test for co2 and observation

Answer 26

bubble colourless and odourless gas through limewater. white precipitate is formed

Question 27

test and observation of oxygen

Answer 27

insert glowing splint into test tube. the colourless and odourless gas evolved relights glowing sprint

Question 28

test and observation for hydrogen

Answer 28

place a lighted splint at mouth of test tube. colourless and odourless gas extinguishes lighted splint with pop sound