Answer
a. Physical
b. Chemical
c. Physical
d. Chemical
Work Step by Step
a. The composition of moth ball does not change during it's sublimation only the state change from solid to gaseous, it is a physical change
b. The hydrofluoric acid reacts with glass, so this is a chemical reaction.
c. During boiling no chemical reaction occurs, only the alcohol is vaporized so it is a physical change
d. Acid reacts with fibers of cotton and chemical changes occurs, so it is a chemical reaction.
