One example of a substance that can burn with an invisible flame is pure hydrogen gas (H₂). When hydrogen gas combusts in the presence of oxygen (O₂), it undergoes a reaction known as combustion or burning. The reaction produces water vapor (H₂O) as the primary product.
The flame produced by burning hydrogen gas is nearly colorless and can be difficult to see under normal conditions. This is because the flame emits very little visible light. However, the heat generated during the combustion process can cause nearby objects to glow, making the flame indirectly visible.
It's important to note that while the flame itself may be difficult to see, hydrogen gas is highly flammable and should be handled with caution. Additionally, burning hydrogen can release a significant amount of heat, making it a potential fire hazard if not properly controlled.