Organic
compound
Alkanes
Test using bromine water
Remains orange when adding bromine water or acidified potassium
dichromate
Changes from orange to colourless when adding bromine water
Alkenes
Decolourise potassium permanganate (KMnO4)
Ceric ammonium nitrate turns yellow-orange to red
Alcohols
Lucas test. 3* alcohol go cloudy immediately, 2* slowly (5-30mins),
and 1* no visible reaction (or little) when adding Lucas reagent (zinc
chloride in conc. hydrochloric acid).
Changes orange to green when adding potassium dichromate
solution (1* and 2* alcohols)
Carboxylic
acid
Fizzes when add magnesium ring
Aldehyde or
Ketone
Forms a precipitate (yellow orange) with 2,4-DNP
(dinitrophenylhydrazine)
Turns blue litmus red
Tollens test. Aldehyde not ketone forms black precipitate with silver
mirror when adding Tollens Reagent (Ag(NH3)2)+
Aldehyde
Silver mirror forms on black precipitate when adding tollens reagent
(a silver ammonia complex)
Ester
Sweet smell…(fails all other tests)
Anion
Test for Presence
Confirmatory Test
Chloride (Cl−)
silver nitrate, white ppt
ppt darkens on UV exposure
Bromide (Br−)
silver nitrate, beige ppt
ppt does not dissolve in 15%
ammonia
lead(II) nitrate, bright yellow
ppt
silver nitrate, pale yellow ppt
Hydroxide (OH−)
silver nitrate, brown ppt.
Blue ppt with Cu 2+
Acetate (CH3COO−)
FeCl3, red complex.
only one not to form ppt with
Ag+ or Pb2+
Carbonate (CO32−)
1M nitric acid, CO2
Silver nitrate, light brown ppt
Sulfate (SO42−)
Barium nitrate, white ppt
ppt does not re-dissolve on
addition of acid
Phosphate (PO43−)
silver nitrate, pale yellow ppt
yellow ppt re-dissolves in nitric
acid
Iodide (I−)
Cation
Test for Presence
Confirmatory Test
Barium (Ba2+)
Sulphate, white ppt
apple-green flame test
Calcium (Ca2+)
brick red flame test
ammonium carbonate, white ppt
Magnesium (Mg2+)
Hydroxide, white ppt
ammonium carbonate, no ppt
Lead(II) (Pb2+)
Iodide, bright yellow ppt
Pale green flame test
Silver (Ag+)
Chloride, white ppt
darkens on UV exposure
Copper(II) (Cu2+)
Hydroxide, blue ppt
Blue-green flame test
Iron(II) (Fe2+)
Iron(III) (Fe3+)
Hydroxide, green ppt
green ppt turns brown in air
Hydroxide, brown ppt
SCN-, blood red complex



Silver is very unreactive
Iron goes gold in flame
Bar, Ca, Mg, Pb make white ppt with NaOH
Definitions, limitations and advantages of acid/base models


N.B. Davy theory states acids contain replicable hydrogen and Lewis
theory states bases provide electrons in a covalent bond and acids
provide none.
Arrhenius
o Acids are compounds that ionise to yield hydrogen ions
o Bases are substances that ionise to yield hydroxide ions
ADVANTAGES
Improves upon previous theories such as Davy
theory by identifying the importance of a
solvent.
Covers a wide range of acids and bases and
straight-forward
DISADVANTAGES
Does not recognise acids/bases that don’t exist in
solution such as CO2
According to his theory, hydrogen ions exist freely
in solution, but in reality, is always hydrated (H3O+)
Does not consider the role of the solvent
Does not account for acid/base substances that
don’t directly yield hydrogen/hydroxide ions such
as NH3

Bronsted/Lowry
o Acids are substances that donate protons
o Bases are substances that accept protons
ADVANTAGES
Clarifies the role of water as a solvent i.e. H3O ions
forms
Improves upon previous theories such as Arrhenius
theory by explaining how substances such as NH3 are
basic
Explains acid strength through the idea that reactions
are equilibrium and acids/bases have conjugates
Theory can be modified to account for solutes other
than water and some reactions in solid or gas phase
DISADVANTAGES
Can't explain reaction between acidic and
basic oxides such as CO2
Can't explain why some substances with
no proton to donate such as BF3 act like
acids