chemical tests Flashcards
what are the cation tests
flame, NaOH, NH3, NH4 +
what are the anion test
halide, SO4, SO3, CO3, NO3
flame test
clean wire with concentrated HCl
dip wire in acid and then in compound
place compound in blue bunsen burner flame
flame color:
Cu
K
Li
Na
Ca
Ba
Mg
blue/green
lilac
bright red
orange/yellow
brick red
apple green
colourless
NaOH/ NH3 test
dissolve sample in water
add drops of NaOH/NH3
observe colour of precipitate
add excess NaOH/NH3
observe colour of precipitate
group 1 NaOH/NH3 test
all colourless
group 2 NaOH/NH3 test
all white solid
Fe 2+ NaOH/NH3 test
all green turns orange solid
Fe 3+ NaOH/NH3 test
all orange/brown
Cu 2+ NaOH/NH3 test
NaOH- blue solid
blue aq
NH3- dark blue solid
dark blue aq
Cr 3+ NaOH/NH3 test
all green/gray solid
Zn 2+ NaOH/NH3 test
NaOH- white solid
colourless aq
NH3- white solid
colourless aq
Al 3+ NaOH/NH3 test
NaOH- white solid
colourless aq
NH3- white solid
white solid
SO4 test
add acid (HCL/ HNO3)
add Ba(NO3)2 or BaCl2
if SO4 present white ppt is formed
SO3 test
add any acid
test gas with K2Cr2O7 or KMnO4
K2Cr2O7- orange to green
KMnO4- purple to faint pink
CO3 test
add any acid
place gas in limewater
if present limewater turns cloudy
NH4 test
react solid with NaOH
heat
collect gas
place damp red litmus paper in gas
if NH4 if present red–> blue
NO3 test
add NaOH to solid
add Al powder
heat
place damp red litmus paper in gas
if NH4 is present red—> blue
halides test
dissolve sample in water
add HNO3
add AgNO3, observe ppt formed
do SO4 test first!
halides results
Cl- white
Br- cream
I- yellow
displacement observation
temp. increase
solid colour change
solution color change
