Final answer:
The correct statement about diffusion is that it is a passive process. It does not require energy as it relies on the distribution of substances from higher to lower concentrations until equilibrium is reached, influenced by factors like molecule size, temperature, and solvent density.
Step-by-step explanation:
Diffusion is a passive process of transport, which means that it does not require any energy input. Instead, diffusion relies on the natural kinetic energy of molecules, which move from regions of higher concentration to regions of lower concentration until a balanced concentration is achieved throughout the medium. This process continues until there is no more concentration gradient, and the substance is equally dispersed.
An everyday example of diffusion is when someone opens a bottle of ammonia in a room. Initially, the ammonia is at its highest concentration inside the bottle. As time passes, the gas will spread out from the bottle to areas with lower ammonia concentration, reaching more and more people with its scent.
Diffusion is not limited to liquids; it can occur in gases and solids as well. Additionally, factors such as molecule size, temperature, and solvent density affect the rate of diffusion. Larger molecules tend to diffuse more slowly, while higher temperatures and lower solvent densities can increase the rate of diffusion.
Considering the given statements, option C, which states 'Diffusion is a passive process,' is the correct answer to the question.