A1-m depth of stagnant water lies on top of a 0.35 cm thickness of nacl. at time t < 0, the water is pure. at time t 0, the salt begins to dissolve into the water. if the concentration of salt in the water at the solid-liquid interface is maintained at saturation (0.00685 mol nacl/cm3) and the diffusivity of nacl is 2.3c-005 cm2/s, independent of concentration, estimate, by assuming the water to act as a semi-infinite medium, the time of salt in the water when: (a) 10% of the salt has dissolved; ; (b) 50% of the salt has dissolved, and (c) 90% of the salt has dissolved. density of nacl 2.165 g/cm3. molecular weight of nacl 58.44 g/mol.