Answer
a. $NH_4Cl$ will produce a solution that contains only ions.
b. $C_2H_5OH$ will produce a solution that contains only molecules.
c. $HCN$ will produce a solution that contains mostly molecules and a few ions.
Work Step by Step
According to the table 9.4 (page 330):
Strong electrolytes produce solutions that contains ions only.
Weak electrolytes produce solutions that contains mostly molecules and a few ions.
Nonelectrolytes produce solutions that contain molecules only.
