The transformation of a solid substance directly into vapor state without changing into liquid is called

The correct answer is option [C] Sublimation. Sublimation is the process whereby a solid substance transitions directly into the vapor phase without passing through the liquid phase. This occurs when the vapor pressure of the solid exceeds the atmospheric pressure at a certain temperature, allowing molecules to escape the solid lattice and enter the gas phase. Common examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and mothballs (naphthalene). Unlike boiling, which involves the conversion of a liquid into vapor, sublimation bypasses the liquid phase entirely. Distillation is a separation technique involving the separation of components in a liquid mixture based on differences in their boiling points. Polymerization is a chemical reaction in which monomers combine to form polymer chains. Thus, only option [C], sublimation, accurately describes the transformation of a solid substance into vapor without becoming a liquid.