Qualitative analysis is used to identify elements by
looking at a change in their color, physical state, solubility and other visible
properties when specific reagents are added to the chemicals being analyzed. There are a
large number of reagents that are used in this process and each element forms a unique
product that can be identified visibly.
To find the
elements present in the powders contained in the bottle, they would first have to be
converted into an aqueous solution. In qualitative analysis, cations are divided into 6
different groups and anions into 3 groups.
The number of
elements that lie in each group is quite large and it would not be possible for me to
list all of them here. You can check for the same at the link provided
below.
Cations of the various groups are identified using
reagents like hydrochloric acid, compounds that can provide a sulfide ion, carbonic
acid, Nessler's reagent, etc. Individual elements form different kinds of compounds with
the reagents that behave differently, for example some dissolve in basic solutions while
others dissolve in acidic solutions. The list of reagents and reactions is a large one
as each element behaves differently.
Cations too can be
detected in ways similar to that of anions. Please look at the details of the reactions
in the link provided below.
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