Question

a candle wick burns with a flame but charcoal does not burn with a flame instead produces smoke. Why?

Answer 1

because it have high capacity of burning

Answer 2

gaseous particles present in the atmosphere are responsible for the visual of flame that we see.

the particles catch fire and appear to be burning with flame.

however charcoal is formed due to destructive distillation.

thus on burning all the volatile substances get evaporated and initially burns with flame but later as no more particles are present no flame is seen.