Question

An unknown substance' A 'is on thermal decomposition produces 'B 'and 'C'.what is 'A' ? An element, a compound or a mixture.

Answer 1

Since A decomposes it cant b an element bcuz elements cant break down.
if it were a mixture the term 'thermal decomposition' would not b used...bcuz it is states a chemical change.
so A has to be a compound.

Answer 2

A is a compound since it decomposes and produces B and C.