Question

q5. after waiting for a long time, the dye molecules in the pie plate will: continue moving in the same manner as when the drop was first placed in the water. slow down, because they have moved to a lower concentration area. stop moving, because they have reached equilibrium. speed up, because they are farther from other dye molecules and have more space to move.

Explanation:

Dye molecules in water undergo diffusion. At equilibrium (after long time), they still move (Brownian motion) but net movement stops. First option: Initial drop has high - low conc. gradient, later equilibrium (same conc. everywhere), but molecules still move as before (random motion). Second: Diffusion rate depends on gradient, but molecules don't slow due to lower conc. area (they move randomly). Third: Molecules never stop moving (kinetic energy). Fourth: Distance from others doesn't speed them up (random motion speed related to temp, not space). So correct is first option.

Answer:

A. Continue moving in the same manner as when the drop was first placed in the water.