Test to distinguish between ZnSO4 and ZnSO3?

1 Answer
1s2s2p
Feb 19, 2018

Add to barium chloride solution followed by around #2cm^3# of dilute #"HCl"#

Explanation:

Barium chloride solution will react with a metal sulphate or metal sulphite to form a metal chloride and barium sulphate or barium sulphite according to one of the following reactions:
#"BaCl"_2+"MSO"_4-> "MCl"_2+"BaSO"_4#
or
#"BaCl"_2+2"MSO"_4-> 2"MCl"+"BaSO"_4#

or

#"BaCl"_2+"MSO"_3-> "MCl"_2+"BaSO"_3#
or
#"BaCl"_2+"M"_2"SO"_3-> 2"MCl"+"BaSO"_3#

(depending on the metal (#"M"#) used.)

In either case, barium sulphate or barium sulphite is produced, which are insoluble in water and therefore form a white precipitate.

However, by adding around #2cm^3# of dilute #"HCl"# the difference can be found. If the reaction produces barium sulphate then the white precipitate will be insoluble in dilute #"HCl"#, however barium sulphite is soluble in #"HCl"#.

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