Question

What does grey coloured residue in charcoal cavity test indicates?

Answer 1

Answer:

Metallic carbonate when heated in a charcoal cavity decomposes to give corresponding oxide. The oxide appears as a coloured residue in the cavity. Sometimes oxide may be reduced to metal by the carbon of the charcoal cavity. The test may be performed as follows: (i) Make a small cavity in a charcoal block with the help of a charcoal borer.

Answer 2

Idk you should know cuz I don't