A borax bead is prepared and heated in the oxidising flame after touching it to a copper(II) salt. The colour of the cold bead is

Ablue
Bgreen
Cviolet
Dcolourless

Answer: A

Copper gives

Cu (BO X_{2}) X_{2}

in the oxidising flame, which is green when hot and blue when cold. Violet is typical of manganese in the oxidising flame and a colourless bead does not indicate copper.

Practice Qualitative Analysis: Anions More on Independent group: sulphate, phosphate, borate

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