$pH + pOH = ?$

What is the $pH$ value of a basic aqueous solution?

$(i)$ State the purpose of developing $pH$ scale.
$(ii)$ Mention the $pH$ range for acids.
$(iii)$ What is the $pH$ of acid rain and how it affects the aquatic life?

When $Zn$ metal is treated with a dilute solution of a strong acid,a gas is evolved,which is utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction involved and also write a test to detect the gas formed.

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

$(a)$ State in tabular form the name of the acid and base from which the following salts are formed. Also,mention the nature of the salt,whether it is acidic or basic?
$(i)$ Sodium acetate.
$(ii)$ Ammonium sulphate.