chemical tests

Question 1

test for carbonate anion (CO32-)

Answer 1

add dilute acid
result: effervescence, CO2 produced

Question 2

test for chloride anion in solution (Cl-)

Answer 2

acidify with dilute nitric acid, then add aqueous silver nitrate
result: white ppt.

Question 3

test for bromide anion in solution (Br-)

Answer 3

acidify with dilute nitric acid, then add aqueous silver nitrate
result: cream ppt.

Question 4

test for nitrate anion in solution (NO3-)

Answer 4

add aqueous sodium hydroxide, then aluminum foil; warm carefully
result: ammonia produced

Question 5

test for sulfate anion in solution (SO42-)

Answer 5

acidify, then add aqueous barium nitrate
result: white ppt.

Question 6

test for ammonium cation (NH4+)

Answer 6

effect of aqueous sodium hydroxide: ammonia produced on warming

Question 7

test for calcium cation (Ca2+)

Answer 7

effect of aqueous sodium hydroxide: white ppt., insoluble in excess
effects of aqueous ammonia: no pt. or slightly white

Question 8

test for copper(II) cation(Cu2+)

Answer 8

effect of aqueous sodium hydroxide: light blue ppt., insoluble in excess
effect of aqueous ammonia: light blue ppt., soluble in excess, giving dark blue solution

Question 9

test for iron(II) cation (Fe2+)

Answer 9

effect of aqueous sodium hydroxide: green ppt., insoluble in excess
effect of aqueous ammonia: green ppt., insoluble in excess

Question 10

test for iron (III) cation (Fe3+)

Answer 10

effect of aqueous sodium hydroxide: red-brown ppt., insoluble in excess
effect of aqueous ammonia: red-brown ppt., insoluble in excess

Question 11

test for zinc cation (Zn2+)

Answer 11

effect of aqueous sodium hydroxide: white ppt., soluble in excess, giving colorless solution
effect of aqueous ammonia: white ppt., soluble in excess, giving colorless solution

Question 12

test for ammonia gas (NH3)

Answer 12

turns damp red litmus paper blue

Question 13

test for carbon dioxide gas (CO2)

Answer 13

turns limewater milky

Question 14

test for chlorine gas (Cl2)

Answer 14

bleaches damp litmus paper

Question 15

test for hydrogen gas (H2)

Answer 15

pops with lighted splint

Question 16

test for oxygen gas (O2)

Answer 16

relights glowing splint

Question 17

flame test for lithium metal (Li+)

Answer 17

red

Question 18

flame test for sodium (Na+)

Answer 18

yellow

Question 19

flame test for potassium (K+)

Answer 19

lilac

Question 20

flame test for copper(II) (Cu2+)

Answer 20

blue-green