Chemical Industries are an essential part of modern life and industrial development. They convert raw materials into useful products used in agriculture, manufacturing, medicine, and daily life. Class 10 Chemistry Chapter 16 covers the basic metallurgical operations, Solvay process for sodium carbonate, manufacture of urea, and petroleum industry.
This chapter is designed to help students understand industrial chemical processes, their applications, and importance. It also includes exam-focused MCQs, short questions, and long questions to make preparation for Class 10 Chemistry exams easier and more effective.
Important MCQs – Chapter 16 Chemical Industries
1. Which compound is formed when ammonia and carbon dioxide react during urea manufacture?
(a) Sodium carbonate
(b) Ammonium nitrate
(c) Ammonium carbamate ✅
(d) Ammonium chloride
2. What is metallurgy?
(a) Study of fertilizers
(b) Study of metals
(c) Extraction of metals from ores ✅
(d) Refining of petroleum
3. Which fertilizer is discussed as important for plant growth?
(a) Ammonium nitrate
(b) Urea ✅
(c) Potassium sulphate
(d) Superphosphate
4. Which industry is highly important in the modern age of communication?
(a) Textile industry
(b) Fertilizer industry
(c) Petroleum industry ✅
(d) Steel industry
5. How many large industrial units came to Pakistan after partition?
(a) 921
(b) 100
(c) 34 ✅
(d) 73
6. What are the two main raw materials used in the manufacture of urea?
(a) Ammonia and methane
(b) Carbon dioxide and nitrogen
(c) Ammonia and carbon dioxide ✅
(d) Nitrogen and hydrogen
Short Questions – Chapter 16 Chemical Industries
1. Explain the process of electrorefining.
Answer:
Electrorefining is a process used to purify metals through the method of electrolysis. In this process, an impure metal is used as the anode, while a pure metal strip serves as the cathode. When an electric current is passed through the electrolyte, metal ions from the anode dissolve into the solution and then deposit on the cathode as pure metal. The impurities in the metal do not dissolve and settle down at the bottom as anode mud. This method ensures that the metal obtained at the cathode is of high purity.
2. What is the principle of Solvay’s process?
Answer:
The principle of Solvay’s process is based on the low solubility of sodium bicarbonate (NaHCO₃) in water. In this process, carbon dioxide (CO₂) is passed through ammonical brine (a solution of ammonia in salt water). As a result, sodium bicarbonate is formed, which precipitates out due to its low solubility. This process is widely used for the industrial manufacture of sodium carbonate (Na₂CO₃) because it is efficient, cost-effective, and produces minimal waste.
3. What are the advantages of Solvay’s process?
Answer:
The major advantages of Solvay’s process are several. Firstly, the raw materials are cheap and easily available, making the process cost-effective. Secondly, carbon dioxide and ammonia are reused, which reduces waste and increases efficiency. Thirdly, it is a pollution-free process, making it environmentally friendly. The process also produces high-purity sodium carbonate, which is suitable for industrial use. Lastly, less fuel is consumed because there is no need to evaporate large solutions, making the process more energy-efficient.
Long Questions – Chapter 16 Chemical Industries
Q1: Write a Note on Fractional Distillation of Petroleum.
Answer:
Definition of Petroleum:
Petroleum is a dark brownish-black oily liquid found beneath the Earth’s crust. It is a mixture of hydrocarbons along with impurities like water, salts, and sand. Petroleum is lighter than water and insoluble in it.
What is Fractional Distillation?
Fractional distillation is a technique used to separate crude oil (petroleum) into different useful components called fractions based on their boiling points. Each fraction contains hydrocarbons with a similar boiling point range.
Process of Fractional Distillation of Petroleum:
First, the crude oil is heated in a furnace up to about 400°C. The oil partially vaporizes and enters the fractionating tower. The fractionating tower is a tall vertical column made of iron or steel, which is hotter at the bottom and cooler at the top. As the vapors rise, they condense at different levels depending on their boiling points. Fractions with high boiling points condense lower in the tower, while fractions with low boiling points condense higher up. Each level of the tower collects a specific fraction.
Main Fractions and Their Uses:
Petroleum gas, which boils below 40°C, is used as LPG and fuel for heating. Petrol (gasoline) with a boiling range of 40–120°C is used as fuel in cars. Kerosene oil boiling between 120–180°C is used for jet fuel and cooking. Diesel oil with a boiling range of 180–250°C is used as fuel in trucks and buses. Fuel oil boiling between 250–350°C is used in industrial boilers. Lubricating oil with a boiling range of 350–400°C is used to make grease and lubricants. The residue, known as bitumen, boils above 400°C and is used for roads (asphalt) and roofing.
Summary:
Fractional distillation is a key process in the petroleum industry. It allows crude oil to be used efficiently by separating it into valuable products that serve as fuels, lubricants, and raw materials for various industrial and domestic purposes.
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