What type of substance is $NaOH$?

Write the balanced chemical equations for the following reactions:
$(a)$ Chlorine is passed over dry slaked lime.
$(b)$ Sodium bicarbonate reacts with dilute hydrochloric acid.
$(c)$ Sodium bicarbonate is heated.

Whose acid-base theory can be applied to aqueous and non-aqueous solutions?

Write the chemical equations for the reactions of zinc granules with:
$(a)$ Sulphuric acid
$(b)$ Hydrochloric acid
$(c)$ Aluminium chloride
$(d)$ Sodium hydroxide
$(e)$ Nitric acid

Why is $HCl$ a stronger acid than acetic acid?

Tooth enamel is the hardest substance in our body. Name the compound of which it is made up. At what $pH$ of the mouth does it get corroded? State the role of bacteria present in the mouth. Suggest a method to prevent tooth decay.