Re: Petrol
Isn't it true though that NO liquids burn
It's all down to how well, as in how efficiently, these things burn. The higher the surface area for the chemical reaction the more efficiently something will burn. This is why gases burn better than liquids which burn better than solids. The burning of liquids is particularly complicated because liquids flow and in a "resting" state the surface area for the reaction is quite static, however creating a mist of the liquid is known to work quite well...
For instance, a mist of petrol droplets will burn considerably better (faster) than a pool of petrol because of the greatly increased surface area of the petrol droplets. It is more complicated than this, of course, because depending on pressure and temperature petrol will turn into a gas, but in essence in a petrol engine it is liquid petrol that is being burned, not a gas. While creating a fine mist of petrol in air will cause some of this petrol to convert into gaseous form this won't happen quickly enough to make much of a difference given the cycle period of a typical internal combusion engine.