The surface areas of four solutes are 2 mm2, 6 mm2, 10 mm2, and 4 mm2. which solute will dissolve the quickest?
a. 2 mm2
b. 4 mm2
c. 6 mm2
d. 10 mm2

I believe the answer is: d. 10 mm2

To dissolve, the molecule of the solute need to contact the with the solvent. Assuming the solute is drown completely. the area of contact with the solvent will be same as the solute surface area. Higher surface area will make the solute dissolved with higher speed. Multiple object with smaller size are known to have more surface area that single object with bigger size.