Maarg Manthan · Topic 13.5

Chemical Industry: Classes and the Heavy Chemical Industry

Geography › Industry · Topic 13.5

The chemical industry makes substances by chemical processes, and it is divided into heavy chemicals (made in bulk, such as sulphuric acid, soda ash and caustic soda), light or fine chemicals (made in small amounts, such as drugs, dyes and perfumes) and petrochemicals. Heavy chemicals are the base of many other industries, and the sector is a large part of world manufacturing.

5 min read · UPSC Prelims · Geography · Industry

At a Glance

Classes Heavy, fine, petrochemicals
Heavy chemicals Sulphuric acid, soda ash, caustic soda
Key raw material Salt, sulphur, limestone, petroleum
World leaders China, United States, Germany, Japan
Indian hubs Gujarat, Maharashtra, Tamil Nadu
Exam link UPSC Prelims, Geography: Industry

Where Does It Fit?

This topic follows the transport equipment industries and takes the industry that uses minerals and petroleum as raw material. It leads to the fertilizer industry, which is a chemical industry of great importance to farming. Previous topic: Automobile, Railway Car, Locomotive, Shipbuilding and Aircraft Industries. Next topic: Fertilizer Industry: Production of Nitrogenous, Phosphatic and Potash Fertilizers.

What Are the Classes of the Chemical Industry?

Class	Examples	Features
Heavy chemicals	Sulphuric acid, nitric acid, hydrochloric acid, soda ash, caustic soda, chlorine	Made in bulk from minerals; used by other industries
Fine and speciality chemicals	Dyes, pigments, drugs, perfumes, pesticides, paints	Made in small amounts; high value; research-driven
Petrochemicals	Plastics, synthetic fibres, synthetic rubber, detergents, solvents	Made from petroleum and natural gas products such as naphtha and ethane
Fertilizers	Urea, ammonium sulphate, superphosphate	Described in Fertilizer Industry: Production of Nitrogenous, Phosphatic and Potash Fertilizers

The chemical industry is called the mother of many industries because paper, textiles, leather, soap, glass, metal, plastics and agriculture all use its products.

How Are the Heavy Chemicals Made?

Sulphuric acid: called the king of chemicals, it is made from sulphur or from pyrites by the contact process, and it is used in fertilizers, refining, batteries, paints and metal cleaning. Its use per head is often taken as a sign of industrial growth.
Soda ash: sodium carbonate, made from salt (brine), limestone and ammonia by the Solvay process, is used in glass, soap, detergents and paper. In India the plants stand on the coast of Gujarat, such as Mithapur, where salt is available.
Caustic soda and chlorine: made by passing electricity through brine in the chlor-alkali process. Caustic soda is used in aluminium, paper, textiles and soap, and chlorine in water treatment, PVC and disinfectants. The process needs cheap power and salt.
Nitric acid and ammonia: made from air and natural gas or naphtha, they are the base of explosives and nitrogenous fertilizers.

Where Is the Chemical Industry Located?

Location factors: raw material (salt, sulphur, limestone, petroleum, gas), cheap power, water, a port for imports and exports, and a nearby market. Plants of heavy chemicals stand near salt fields and ports; petrochemical complexes stand near refineries.
World: China is the largest chemical producer, followed by the United States, Japan, Germany and South Korea. Germany’s Rhine valley, with Ludwigshafen, is an old centre. The Gulf coast of the United States around Houston is the largest petrochemical belt, and the Gulf states and Singapore have large complexes. Check the latest ranks.
India: the chemical sector is among the largest in Asia and includes bulk chemicals, specialty chemicals, agrochemicals and pharmaceuticals. Gujarat (Vadodara, Bharuch, Dahej, Jamnagar) is the leading state, followed by Maharashtra (Mumbai-Thane, Raigad), Tamil Nadu, Andhra Pradesh, Odisha (Paradip) and West Bengal (Haldia).
Policy: the government supports Petroleum, Chemicals and Petrochemicals Investment Regions (PCPIRs), set up under a 2007 policy, with sites at Dahej, Paradip, Visakhapatnam-Kakinada and Cuddalore-Nagapattinam, and pushes for lower import dependence on key chemicals.
Issues: pollution from effluent and gases, safety risks and the need for strict rules. Cleaner processes and effluent treatment plants are required.

Figures for output and rank change often, so check the latest data when quoting them.

Why Does the Chemical Industry Matter and What Are Its Risks?

Links to other industries: textiles use dyes and synthetic fibre, paper uses caustic soda and chlorine, glass uses soda ash, metal industries use acids, and farming uses fertilizers and pesticides. A shortage of a basic chemical can slow many industries at once.
Jobs and trade: the sector employs many skilled workers and earns export income from speciality chemicals, dyes and drugs. Countries such as Germany and Switzerland earn much from fine chemicals.
Hazards: toxic gases, fires and spills can cause disasters. The Bhopal gas leak of December 1984, from a pesticide plant, is the worst industrial disaster in India and led to the Environment (Protection) Act, 1986 and stricter rules on hazardous industries.
Cleaner shift: green chemistry, recycling of waste acids and zero liquid discharge plants are being adopted to cut the harm to rivers and air.

Why Is This Topic Important?

Classes Heavy, fine, petro
Raw material Salt, sulphur, limestone, oil
Hubs Gujarat coast, Houston, Rhine

What Came Next?

The next topic describes the fertilizer industry: nitrogenous, phosphatic and potash fertilizers. Next topic: Fertilizer Industry: Production of Nitrogenous, Phosphatic and Potash Fertilizers.

Key People and Terms

Contact process Making sulphuric acid
Solvay process Making soda ash
Chlor-alkali Caustic soda and chlorine from brine
Brine Strong salt solution
Naphtha Petroleum fraction used as feedstock
PCPIR Petroleum, chemicals and petrochemicals region

Exam Corner

Points to Remember

Sulphuric acid is the king of chemicals.
Soda ash comes from the Solvay process.
Caustic soda needs cheap power and brine.
Dahej is a PCPIR site.
Gujarat leads in chemicals.

Do Not Confuse With

Heavy and fine chemicals Bulk and low unit value versus small and high value
Soda ash and caustic soda Sodium carbonate versus sodium hydroxide
Contact and Solvay process Sulphuric acid versus soda ash

Memory Hook

Salt, sulphur, lime and oil: heavy in bulk, fine in kind, the base of a hundred industries.

Mains Angle

Questions ask for the importance of the chemical industry and the factors for its location. These points add depth.

Role Input to other industries
Location Coast, refinery, salt
Issues Pollution and safety

A Question You May Face

An original practice question, not a past paper question.

“Discuss the classification of the chemical industry and explain the factors for the location of heavy chemical industries in India.”

How to Answer

Classes Heavy, fine, petrochemicals.
Products Acid, soda ash, caustic soda.
Location Salt, power, port, refinery.
Issues Pollution and policy.

GS Relevance

Prelims: classes of chemicals, raw materials, centres, products. GS Paper 3: industry, petrochemicals, chemical hubs.

Frequently Asked Questions

Why is sulphuric acid called the king of chemicals?

Sulphuric acid is called the king of chemicals because it is used in making fertilizers, dyes, paints, explosives, batteries and in refining petroleum and cleaning metals. It is made from sulphur or pyrites by the contact process, and the amount used by a country is often taken as an index of its industrial development.

What are the main classes of the chemical industry?

The chemical industry has three main classes: heavy chemicals, made in bulk, such as sulphuric acid, soda ash and caustic soda; fine and speciality chemicals, such as dyes, drugs and perfumes, made in small amounts; and petrochemicals, made from petroleum and natural gas, such as plastics, synthetic fibres and detergents.

What is the Solvay process?

The Solvay process is the method used to make soda ash, or sodium carbonate, from common salt, limestone and ammonia. Soda ash is used to make glass, soap, detergents and paper. In India, plants using the process stand on the Gujarat coast, such as Mithapur, where salt is available in large quantity.

Which Indian states lead in chemical production?

Gujarat is the leading chemical state of India, with hubs at Vadodara, Bharuch, Dahej and Jamnagar, followed by Maharashtra, Tamil Nadu, Andhra Pradesh, Odisha and West Bengal. These states have refineries, ports, salt and power. Petroleum, Chemicals and Petrochemicals Investment Regions have been set up at several of these places.

What is a petrochemical?

A petrochemical is a chemical product made from petroleum or natural gas, such as plastics, synthetic fibres, synthetic rubber, detergents and solvents. Raw materials like naphtha and ethane come from refineries and gas processing, so petrochemical complexes are located near refineries and ports, as at Jamnagar, Dahej, Haldia and Paradip.

PYQ Practice — Statement Analysis

1 Soda ash is made by the Solvay process.

True

It uses salt, limestone and ammonia.

2 Sulphuric acid is made by the Haber process.

False

It is made by the contact process; the Haber process makes ammonia.

3 Caustic soda is made by passing electricity through brine.