18.From the following list of aqueous solutions and water, select the one with the highest boiling point. a.1.0 mKNO3b.2.0 mC12H22O11(sucrose)c.0.75 mNaCld. pure watere.0.75 mCuCl2

e. 0.75m CuCl

Explanation:

The boiling point of a solvent increases with the addition of moles of solute. The formula is:

ΔT = i×Kb×m

Where ΔT is boiling point elevation, i is Van't Hoff factor, Kb is ebulloscopic constant and m is molality of solution.

That means the higher i×m, the highest boiling point. Thus:

a. 1.0m KNO₃: i×m = 2ₓ1.0m = 2

b. 2.0m C₁₂H₂₂O₁₁: i×m = 1ₓ2.0m = 2

c. 0.75m NaCl: i×m = 2ₓ0.75m = 1.5

e. 0.75m CuCl: i×m = 3ₓ0.75m = 2.25

e. 0.75m CuCl has the highest boiling point

it is b that is the answer.