In which phase transition do molecules directly move from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles?
a. evaporation
b. sublimation
c. freezing
d. deposition

The question says,'in which phase transition do molecules directly move from a state involving vibration of particles in a fixed position to a state involving random movement of high speed particles. The correct option is B. Sublimation is a phase change process during which a solid is converted directly to the gaseous form.

The correct answer to this question is B.sublimation