What is contact process

See below

Step-by-step explanation:

The contact process is an Industrial method of producing sulfuric acid.

Step 1. Conversion of S to SO₂

Molten sulfur is burned in an excess of air.

S (ℓ) + O₂ (g) ⟶ SO₂ (g)

Step 2. Conversion of SO₂ to SO₃

The hot mixture of SO₂ and excess air at about 425 °C and 1.5 atm is passed over a hot V₂O₅ catalyst.

SO₂ (s) + O₂ (g) ⇌ SO₃ (g)

The SO₂ is converted to SO₃ in an equilibrium reaction.

Step 3. Conversion of SO₃ to H₂SO₄

(a) The SO₃ is dissolved in concentrated H₂SO₄.

SO₃ (g) + H₂SO₄ (ℓ) ⟶ H₂S₂O₇ (ℓ)

The product is fuming sulfuric acid.

(b) Then, enough water is added to react with the dissolved SO₃ and form concentrated H₂SO₄.

H₂O (ℓ) + H₂S₂O₇ (ℓ) ⟶2H₂SO₄ (ℓ)