ANS:D - none of these

Leaching rate can depend on several factors, including agitation, temperature, and particle size. Therefore, the statement "Leaching rate is independent of agitation, temperature, particle size" is incorrect. Here's why each factor can affect leaching rate:

1. Agitation: Agitation enhances the contact between the solid phase (e.g., ore) and the leaching solution, promoting mass transfer and increasing the leaching rate. Intense agitation can help maintain a high concentration gradient at the solid-liquid interface, leading to faster leaching.
2. Temperature: Temperature influences the kinetics of chemical reactions, including those involved in leaching processes. Typically, higher temperatures increase reaction rates by providing more energy for reactant molecules to overcome the activation energy barrier. Therefore, elevated temperatures often result in faster leaching rates.
3. Particle size: The surface area-to-volume ratio increases as particle size decreases. Finely ground particles have more surface area available for contact with the leaching solution, facilitating faster mass transfer and enhancing leaching rates compared to larger particles.

In summary, agitation, temperature, and particle size can all significantly affect leaching rates, and the leaching rate is not independent of these factors. Each factor influences the rate of mass transfer and chemical reactions occurring during the leaching process.