Q. Does chalk powder burn?

Answer

In most cases, chalk will not catch fire when it is exposed to heat. Burning chalk demands not only a very high temperature but also, preferably, a very high pressure, both of which are conditions that are very unlikely to be present under normal conditions. However, when it is in the form of dust or powder, it acts completely differently. The dust makes it possible for there to be more oxygen in the environment, and it has the ability to enable chalk dust to burn pretty fast and even burst in certain circumstances. Many different substances will behave in this manner and become significantly more flammable when they are in dust form. And yet, chalk has the potential to act as an explosive. That's not because we have been intentionally deceiving you about how difficult it is to burn chalk; rather, there are specific conditions under which chalk becomes explosive. To be more specific, it needs to be in the air and in the form of fine dust.