Nursing Entrance Exam (NEX) Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success!

The process illustrated by the spreading out of ammonia vapor in a closed room is diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration until equilibrium is reached. In the case of ammonia vapor, the molecules move through the air in the closed room, dispersing from the concentrated source of the vapor and evenly mixing with the surrounding air due to their kinetic energy.

This phenomenon is crucial in various scientific and everyday contexts, such as in respiratory processes, where oxygen diffuses from areas of higher concentration in the alveoli of the lungs into the bloodstream. It is also observed in the mixing of gases and liquids, highlighting how substances can spread throughout a medium.

The other processes, such as imbibition, inhibition, and assimilation, relate to different biological or chemical phenomena that do not accurately describe the spreading of gases. Imbibition typically refers to the absorption of water by solids, inhibition involves the reduction or prevention of certain processes, and assimilation pertains to the incorporation of nutrients into an organism's body. Thus, diffusion is the correct and relevant term for the scenario of ammonia vapor dispersing in a closed space.