Chemistry Qualitative Analysis

Table of Contents

Qualitative Analysis

Invariably involves detection or identification of cation(s) and or anion(s) present in given test substance in a series of reactions.

this is an informed guess about the possible identity of the test substance based on its physical appearance.

Nature of test substance	Preliminary Deduction
White cystalline solid	not likely to be a transition metal compound (usually coloured). not likely to be an oxide/carnonates (powders). likely to have water of crystallization.
White powder	not likely to be a transition metal compound likely to be an oxide/carnonates/slphates of non-trans element. manganese carbonate is almost white.
Coloured crystalline	likely to be a transition metal compound (nitrates /halides /some sulphates of trans metals)
Coloured powder	likely to be caronate of transition metal e.g CuCO₃ is green powder. it can be a sulphate/ another compound of a trans metal which has lost its ater of crystallisation. red lead oxide, Pb₃O₄ (non-transition element).
Black powder	likely to be a metal sulphide/ oxide of a transition metal/ non most metal sulphides are black powders eg PbS

Nature of test substance	Preliminary deduction
Clear colourless solution	no transition cation /oxoanion /complex present substance is soluble
A strangely coloured solution	likely to be a mixture of trans metal cation(s). if solution is a mixture of trans cations, 2⁰ colours of two cations should be expected eg Fe³⁺(a) -redbrown and Cu²⁺(aq) -blue = grey green colour
A clear colured solution	a transition metal/ oxoanion/ complex is likely to be present. maybe mixed with a soluble compound of a non transition metal