10th Class Chemistry Chapter 16 Notes | Get Now
10th Class Chemistry Chapter 16 Notes cover one of the most important and scoring units of the Matric syllabus — Chemical Industries. This chapter explains how raw ores are converted into pure metals, how sodium carbonate and urea are manufactured, and how petroleum is refined into useful products. These 10th Class Chemistry Chapter 16 Notes are designed to help students understand every process, reaction, and diagram in a simple, exam-focused way.
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Students preparing for board exams often find this chapter heavy because of the multiple industrial processes involved. That’s why these 10th Class Chemistry Chapter 16 Notes break down each topic — metallurgy, Solvay’s process, urea manufacturing, and petroleum refining — into short, easy-to-revise sections.
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What This Chapter Covers
Chapter 16 of 10th Class Chemistry is titled “Chemical Industries.” It focuses on the practical, real-world applications of chemistry in industries operating in Pakistan and around the world. The main topics include:
- Concentration of ore and its methods
- Roasting, smelting, and bessemerization
- Electrolytic refining of copper
- Solvay’s process for sodium carbonate
- Manufacturing of urea
- Origin, refining, and fractions of petroleum
Metallurgy and Concentration of Ore
Metallurgy is the science of extracting metals from their ores. Before a metal can be extracted, the ore must be purified through a process called concentration — the removal of gangue (impurities) from the ore.
Methods of Concentration
According to these 10th Class Chemistry Chapter 16 Notes, there are three main methods used for ore concentration:
1. Gravity Separation
This method uses the difference in densities between the ore and gangue particles. Heavy ore settles down in a stream of water while lighter gangue particles are carried away.
2. Froth Flotation Process
This process depends on the wetting properties of ore and gangue. Ore particles get coated with oil and rise to the surface as froth, which is then skimmed off. Pine oil plays a key role in helping the froth form and remain stable.
3. Electromagnetic Separation
This method separates magnetic ore particles from non-magnetic impurities using electromagnets. It works well for ores like magnetite.
Roasting, Smelting, and Bessemerization
After concentration, the ore goes through three major stages to become a pure metal. These stages are frequently tested in exams, so understanding them clearly is essential.
Roasting
Roasting is the process of heating the concentrated ore to a high temperature in excess of air. For example, copper pyrite (CuFeS₂) is roasted to form a mixture of cuprous sulphide and ferrous sulphide, while impurities escape as volatile oxides.
Smelting
Smelting involves further heating of the roasted ore along with sand (flux) and coke in a blast furnace. This is a highly exothermic process, so only a small amount of coke is needed. During smelting:
- Ferrous sulphide oxidizes to ferrous oxide
- Ferrous oxide reacts with sand to form slag (FeSiO₃)
- Slag rises to the top and is removed
- A molten mixture called matte (containing about 45% copper) is collected from the bottom
Bessemerization
Bessemerization is carried out in a pear-shaped Bessemer converter. Molten matte is mixed with sand and heated with a hot air blast. This step removes remaining impurities and produces blister copper, which is about 98% pure.
Refining of Copper
Refining is the final step used to purify blister copper into nearly 100% pure metal. This is done through electrolytic refining.
In this process:
- Impure copper acts as the anode
- Pure copper acts as the cathode
- Copper sulphate solution acts as the electrolyte
- On passing current, Cu²⁺ ions move from anode to cathode
- Pure copper deposits on the cathode
- Impurities like gold and silver settle as anode mud
This section of the 10th Class Chemistry Chapter 16 Notes is important because refining-related questions appear frequently in board papers.
Solvay’s Process for Sodium Carbonate
Solvay’s process is based on the low solubility of sodium bicarbonate at low temperature (15°C). When CO₂ is passed through ammonical brine, NaHCO₃ precipitates out.
Raw Materials Used
- Sodium chloride (brine)
- Limestone (CaCO₃)
- Ammonia gas (NH₃)
Steps Involved in Solvay’s Process
- Preparation of ammonical brine – Ammonia gas is dissolved in brine
- Carbonation – CO₂ is passed through ammonical brine to form NaHCO₃
- Filtration – NaHCO₃ precipitates are filtered out
- Calcination – NaHCO₃ is heated to produce sodium carbonate
- Preparation of CO₂ and slaked lime – Limestone is heated in a lime kiln
- Ammonia recovery – Ammonia is recovered and reused in the process
Advantages of Solvay’s Process
- Cheap raw materials
- CO₂ and ammonia are recycled
- Pollution-free (only waste is calcium chloride)
- High-purity sodium carbonate
- Low fuel consumption
Manufacturing of Urea
Urea is a nitrogenous fertilizer containing 46.6% nitrogen. It is a white crystalline compound, highly soluble in water, and used mainly as a fertilizer (about 90% of production).
Raw Materials
- Ammonia (NH₃), prepared via Haber’s process
- Carbon dioxide (CO₂)
Stages of Urea Manufacturing
- Reaction of ammonia and CO₂ – forms ammonium carbamate
- Urea formation – ammonium carbamate dehydrates with steam to form urea
- Granulation – liquid urea is sprayed and dried into granules for storage
Urea is also used to make explosives and to reduce NOₓ pollutants in vehicle exhaust systems, in addition to its role as a fertilizer.
Origin and Refining of Petroleum
Petroleum, meaning “rock oil,” is a complex mixture of hydrocarbons formed from the decomposition of dead plants and animals buried under the Earth’s crust millions of years ago.
How Petroleum Was Formed
High pressure, temperature, and bacterial activity converted buried organic matter into crude oil over millions of years. Being lighter than water, it rises and gets trapped between layers of impervious rock.
Fractional Distillation of Petroleum
Refining separates crude oil into useful fractions based on differences in boiling points. The process is called fractional distillation and is carried out in a fractionating column.
Major Fractions of Petroleum
| Fraction | Carbon Range | Boiling Range | Main Use |
|---|---|---|---|
| Petroleum Gas | C1–C4 | Up to 25°C | LPG, fertilizer production |
| Petroleum Ether | C5–C7 | 30–80°C | Lab solvent, dry cleaning |
| Gasoline | C7–C10 | 80–170°C | Motor fuel |
| Kerosene Oil | C10–C12 | 170–250°C | Domestic fuel, jet fuel |
| Diesel Oil | C13–C15 | 250–350°C | Heavy vehicles |
| Fuel Oil | C15–C18 | 350–400°C | Ships, industrial furnaces |
Residual oil, left after distillation, is further processed to obtain lubricants, paraffin wax, asphalt, and petroleum coke.
Natural vs Chemical Fertilizers
This chapter also compares natural and synthetic fertilizers:
Natural Fertilizers
- Improve soil porosity and structure
- Increase moisture-holding capacity
- Contain minimal toxic chemicals
Chemical Fertilizers
- Release nutrients quickly
- Have short-lived effects, requiring repeated application
- Overuse may burn plants instead of helping them grow
For more chapter-wise notes, visit [internal link] to access complete 10th Class Chemistry resources on TaleemWorld.com.
Why These Notes Matter for Exam Preparation
These 10th Class Chemistry Chapter 16 Notes are structured to match the board exam pattern, covering long questions, short questions, and multiple-choice questions. Practicing diagrams like the blast furnace, Bessemer converter, and Solvay process flow chart can significantly improve scoring in this chapter.
Students should also revise important reactions repeatedly, as chemical equations from this chapter are commonly asked in both objective and subjective exam papers.
FAQs
Q1. What is covered in 10th Class Chemistry Chapter 16 Notes?
These notes cover metallurgy, ore concentration, roasting, smelting, bessemerization, copper refining, Solvay’s process, urea manufacturing, and petroleum refining, along with important diagrams and reactions for exam preparation.
Q2. What are the three main steps of metallurgy?
The three main steps are concentration of the ore, extraction of the metal, and refining of the metal. Each step removes different types of impurities to produce a pure metal from its raw ore.
Q3. What is the principle behind Solvay’s process?
Solvay’s process works on the principle that sodium bicarbonate has low solubility at 15°C. When CO₂ passes through ammonical brine, NaHCO₃ precipitates out and is later converted into sodium carbonate.
Q4. Why is urea considered an important fertilizer?
Urea contains 46.6% nitrogen, the highest among common fertilizers. It’s non-toxic, non-explosive, and used for nearly all crop types, making it the most widely used nitrogenous fertilizer worldwide.
Q5. What is blister copper?
Blister copper is the product formed after bessemerization. It is about 98% pure copper, with blisters on its surface caused by escaping dissolved gases during cooling.
Q6. Which petroleum fraction is used for jet fuel?
Kerosene oil, specifically a special refined grade, is used as jet fuel. Regular kerosene is also commonly used as a domestic fuel for heating and lighting purposes.