Answer
(a) Dim
(b) Light
(c) Dark
Work Step by Step
(a) Hydrofluoric acid $(HF)$ is a weak electrolyte (according to the table 4.1, Page 118); therefore, the light bulb will only receive part of the electricity.
(a) Sodium chloride ($NaCl$) is an ionic compound, which is very dissociated in water. Therefore, the solution will be very conductive.
(b) Glucose is a very molecular compound, which makes it a bad conductor in water.
