Introduction:
Inorganic chemicals are substances that do not contain carbon bonded to hydrogen atoms. They are generally derived from minerals and non-living sources. Inorganic chemicals are widely used in various industries such as agriculture, pharmaceuticals, and manufacturing.

Explanation:
The given options are:
a) Sulphuric acid
b) Petrochemicals
c) Nitric acid
d) Alkalies

Sulphuric acid:
- Sulphuric acid (H2SO4) is an inorganic chemical compound.
- It is one of the most widely used industrial chemicals.
- It is used in the production of fertilizers, dyes, detergents, and batteries.

Petrochemicals:
- Petrochemicals are organic chemicals derived from petroleum or natural gas.
- They include products such as plastics, synthetic fibers, rubber, and solvents.
- Petrochemicals are not considered inorganic chemicals as they contain carbon bonded to hydrogen atoms.

Nitric acid:
- Nitric acid (HNO3) is an inorganic chemical compound.
- It is a strong acid used in various industries, including explosives, fertilizers, and dyes.
- Nitric acid is produced from the oxidation of ammonia.

Alkalies:
- Alkalies are inorganic compounds that are soluble in water and produce hydroxide ions (OH-) when dissolved.
- Examples of alkalies include sodium hydroxide (NaOH) and potassium hydroxide (KOH).
- Alkalies are considered inorganic chemicals.

Conclusion:
Based on the given options, the correct answer is b) Petrochemicals. Petrochemicals are organic chemicals derived from petroleum or natural gas and contain carbon bonded to hydrogen atoms. The other options, sulphuric acid, nitric acid, and alkalies, are all inorganic chemicals as they do not contain carbon bonded to hydrogen atoms.