Study Set Content:
any process wherein new chemical substance is formed
Reaction
test conducted to find final proof of the or absenceo the ion.
- are the tests required to confirm the analysis.
Confirmatory test
a methodd where in supernatant liquid is poured off to another
test tube.
Decantation
precipitated with hydrogen sulfide in 0.3M acid
concentration. Subdivided into two subgroups that are separated with
sodium sulphide reagent which is composed of:
Hydrogen sulfide group
forms amphoteric hydroxides, which are insoluble
but dissolve in excess of sodium hydroxide.
Aluminum subgroup
precipitated with HCl of any soluble chloride from their
aqueous or dilute acid solution.
Silver Group
precipitated by hydrogen sulphide or
ammonium sulphide from their ammoniacal solutions.
Ammonium sulphide group
Addition of 95% alcohol completes the precipitation
of Mg+2 as double salt.
Alkaline Earth Group
the hydroxides and sulphides are insoluble in excess of
the alkali .
Iron subgroup
hypothetical alkali
NH4
+
oxidizes the ions into their higher oxidation states
Na2S2
– aka “Soluble group” cations form soluble chloride sulphides,
hydroxides, and carbonates.
Alkali Group
their sulphides are insoluble in sodium sulphide
reagent.
Copper subgroup
prevents the hydrolysis of the sulfides
NaOH
precipitates the sulphide of the ions
Na2S
– their sulphides are soluble in sodium sulfide reagent
forming the sulfo or thio of the higher oxidation states.
Tin subgroup
Group III
Ammonium Sulfide Group
Group II
Hydrogen Sulfide Group
Pb reagent and color
K2CrO4, yellow ppt
Sb+3 reagent and color
NaOBr and insoluble
