All u nid to kno abt salts

Question 1

Soluble salts

Answer 1

all soluble
(NO3 CH3COOH)
(K Na NH4)

Cl (Exp PAH)
SO4 (Exp PABC)

all insoluble Exp all soluble
(CO3, Pb )

Question 2

preparation for insoluble salts

Answer 2

Double decomposition reaction

1. Choose a soluble salt solution containing cation of the insoluble salt
2. Choose a soluble salt solution containing anion of the insoluble salt
3. Mix two solutions
4. Filter, wash and dry the precipitate

Question 3

preparation for soluble salts

not K Na NH4

Answer 3

acid metal
acid metal oxide
acid metal hydroxide
acid metal carbonate

1. Add excess solid to hot dilute acid
2. Filter off the unreacted solid
3. Evaporate to saturate the salt solution
4. Cool to allow crystallisation to occur
5. Filter, wash and dry crystals

Question 4

preparation for soluble salts

K Na NH4

Answer 4

Neutralisation reaction

1. Use titration method to neutralise a given volume of acid to obtain the salt solution
2. Evaporate to saturate the salt solution
3. Cool to allow crystallisation to occur
4. Filter, wash and dry the crystals

Question 5

solid zinc oxide

Answer 5

yellow when hot

white when cold

Question 6

solid lead2 oxide

Answer 6

brown when hot

yellow when cold

Question 7

chromate 6 ion

Answer 7

yellow

Chromium3 ion is green

Question 8

dichromate 6 ion

Answer 8

orange

Question 9

manganate7 ion

Answer 9

purple

Question 10

iron 2 ion

Answer 10

green

Question 11

iron 3 ion

Answer 11

brown

Question 12

copper 2 ion

Answer 12

blue

Question 13

lead 2 chloride
lead 2 bromide
lead 2 iodide

Answer 13

insoluble in cold water

soluble in hot water

Question 14

iron2 ions
nickel2 ions
chromium3 ion

Answer 14

dissolve in water to produce green solutions

Question 15

test for ammonia gas

Answer 15

bring a piece of moist red litmus paper to the mouth of the tt

(red litmus paper turns blue)

Question 16

test for oxygen gas

Answer 16

lower a glowing wooden splint into the tt

glowing wooden splint is relighted

Question 17

test for carbon dioxide gas

Answer 17

bubble the gas thru limewater

limewater turns milky

Question 18

test for hydrogen gas

Answer 18

bring a lighted wooden splint to the mouth of the tt

Gas burns with a pop sound

Question 19

test for chlorine gas

Answer 19

bring a piece of moist blue litmus paper to the mouth of the tt

(blue litmus paper turns red the bleached)

Question 20

test for sulphur dioxide gas

Answer 20

bubble the gas thru acidified dichromate solution or acidified purple acidified manganate 4 ion

(the orange acidified dichromate solution turns green
the purple potassium manganate turns colourless)

Question 21

test for hydrogen chloride gas

Answer 21

use a glass rod to bring a drop of concentrated ammonia solution to the mouth of the tt

(dense white fumess are formed)

Question 22

test for nitrogen dioxide gas

Answer 22

bring a piece of moist blue litmus paper to the mouth of the tt
observe the colour of gas evolved

(blue litmus paper turns red)
(brown gas is evolved)

Question 23

characteristics of ammonia gas

Answer 23

colourless gas
pungent smell
alkaline gas
turns moist red litmus paper blue
form dense white fumes with hydrogen chloride

(produced by heating a mixture of ammonium salt and alkali)

Question 24

characteristics of oxygen gas

Answer 24

colourless gas
no effect on litmus paper
supports combustion
relights a glowing wooden splint

(produced by heating a chlorate5 or nitrate salt)

Question 25

characteristics of carbon dioxide gas

Answer 25

colourless gas acidic gas turns mist blue litmus paper red turns limewater milky (produced by heating a metal carbonate or acid-carbonate reaction)

Question 26

characteristics of hydrogen gas

Answer 26

colourless gas no effect on litmus paper forms an explosive mixture with air burns with pop sound (produced by an acid-metal reaction)

Question 27

characteristics of chlorine gas

Answer 27

``` greenish-yellow gas choking smell acidic gas turns moist blue litmus paper red bleaches litmus paper ``` (produced by heating a mixture of manganese 4 oxide and concentrated hydrochloric acid)

Question 28

characteristics of sulphur dioxide gas

Answer 28

colourless gas pungent smell acidic gas turns moist blue litmus paper red reduces orange acidified dichromate 6 ion to green chromium3 ion decolourises purple acidified manganate 7 ion (produced by an acid-sulphite reaction)

Question 29

characteristics of hydrogen chloride gas

Answer 29

``` colourless gas forms fumes in moist air acidic gas turns moist blue litmus paper red forms dense white fumes with ammonia gas ``` (produced by heating a mixture of common salt and concentrated sulphuric acid)

Question 30

nitrogen dioxide gas

Answer 30

``` brown gas pungent smell acidic gas turns moist blue litmus paper red reacts with water to form colourless solution ``` (produced by heating a nitrate salt)

Question 31

action of heat on carbonate salts

Answer 31

all salts produce metal oxide and carbon dioxide potassium, sodium do not decompose silver produce metal, oxygen and carbon dioxide ammonium produce ammonia, water and carbon dioxide

Question 32

action of heat on nitrate salts

Answer 32

all salts produce metal oxide, nitrogen dioxide, oxygen potassium, sodium nitrate salt and oxygen silver produce metal, nitrogen dioxide, oxygen ammonium produce nitrous oxide and water

Question 33

iron2 oxide salt | copper2 oxide

Answer 33

black solid

Question 34

test for carbonate ion

Answer 34

add dilute hydrochloric acid bubble gas thru limewater (limewater turns milky)

Question 35

test for chloride ion

Answer 35

add dilute nitric acid add silver nitrate solution (a white precipitate is obtained) nitirc acid prevent precipitation of silver sulphate and silver carbonate

Question 36

test for sulphate ion

Answer 36

add dilute hydrochloric acid add barium chloride solution (a white precipitate is obtained) hydrochloric acid prevent precipitation of barium carbonate

Question 37

test for nitrate ion | Brown ring test

Answer 37

add dilute sulphuric acid add iron2 sulphate solution shake to mix well carefully add concentrated sulphuric acid down the side of the tt