The contact process is used for the industrial production of
sulfuric acid (H2SO4)
Hydrochloric acid (HCl)
Sodium hydroxide (NaOH)
Calcium oxide (CaO)
Correct answer is A
The contact process is used for the industrial production of sulfuric acid (H2SO4), not any of the options provided. The process involves the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3) which is then absorbed in sulfuric acid to form oleum (H2S2O7). The oleum is then diluted with water to form sulfuric acid.