Question

some solid change directly into gas on heating without passing through a liquid phase.Give the reason why???

Answer 1

Why do solids change directly to vapours on heating without passing through the liquid phase

Many compounds do pass through a liquid phase before turning into a gas phase. The reason some do not is because the pressure in the vessel they are in plays a big part in the temperature at which they melt. Even solid CO2 will melt at the right temperature and pressure. Look up triple points in tour chemistry textbook.