Test For Ionssss AS AND A2 KNOWLEDGE

Question 1

what turns damp red litmus paper blue ? gas ?1

Answer 1

ammonia

Question 2

what turns damp blue litmus paper red?1

Answer 2

chlorine

Question 3

Agno3 colours ? + hno3

3

Answer 3

cl-white ppt
br-cream ppt
I-yellow ppt

Question 4

after the Agno3 test , you can add ammonia to differentiate ? how ?
3

Answer 4

cl - add dilute ammonia =colourless solution
Br- add concentrated ammonia solution = colourless solution
I- doesn’t dissolve even in Concentrated solution

Question 5

2 tests for alkene? why does this happen ?
mechanism ?
4

Answer 5

1) add bromine water should turn colourless
- the Br adds to the double bond so the alkene becomes a halogenoalkane =electrophilic addition
2) potassium manganate + DILUTE sulphuric acid = PURPLE–> COLOURLESS

Question 6

add PCl5 to organic liquid ?
add ammonia ?
3

Answer 6

• test for OH group
• should show misty fumes if OH group is present (damp litmus will turn RED) misty fumes of HCL
• makes white smoke with ammonia

Question 7

test for CO2 ? 1

Answer 7

limewater turns cloudy

Question 8

why can’t we test for fluoride ions using AgNo3 ? 3

Answer 8

-it is soluble in water so no ppt would form

Question 9

Halogenoalkanes are able to undergo nucleophilic substitution reactions because …
2

Answer 9

They have a polar C-X bond with dipoles on C and X

Question 10

halogenoalkane+ aq KOH

Answer 10

Alcohol

Question 11

halogenoalkane+ ethanolic KOH

Answer 11

Alkene

Question 12

Test for ammonium ions ?

3

Answer 12

• add dilute NAOH

- ammonia gas : damp red litmus paper —> blue

Question 13

Test for nitrate ions :3

Answer 13

• add nitrate to NAOH
• add powdered Aluminium
• ammonia gas ( red —> blue litmus paper )

Question 14

what an anion ?

Answer 14

Negatively charged species

Question 15

what’s a cation ?

Answer 15

positively charged species