Question

the process which a substance changes directly from solid to gaseous form and vice versa is called​

Answer 1

Sublimation is the conversion of a substance from the solid to the gaseous state without its becoming liquid.

Answer 2

Sublimation is the process of transformation directly from the solid phase to the gaseous phase, without passing through an intermediate liquid phase. ... Also, at pressures below the triple point pressure, an increase in temperature will result in a solid being converted to gas without passing through the liquid region.