Chemistry, SSC-KPK Class 10. This chapter is split into 25 topics and has
548 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Topics in this chapter
Organic and synthetic fertilizers (STS box)20 questions
Fractions of petroleum and their uses (Table 16.1)25 questions
Solvay plant diagram and flow sheet (Fig 16.2, 16.3)22 questions
Urea flow sheet diagram (Fig 16.5)21 questions
Molecular size and properties of petroleum fractions21 questions
Numerical exercises on petroleum fractions21 questions
Calculations on the Solvay process25 questions
Electro-refining of copper22 questions
Fractional distillation of petroleum (Fig 16.6)23 questions
Fertilizers and urea: introduction and raw materials21 questions
Sodium carbonate and the raw materials of the Solvay process21 questions
Main process and reactions of the Solvay process20 questions
Petroleum: meaning, importance and producing countries21 questions
Concentration of ores and froth flotation24 questions
Manufacture of urea: conditions and reactions21 questions
Calculations on urea24 questions
Urea plant diagram (Fig 16.4)24 questions
Review of chemical industries21 questions
Roasting, matte and reduction to blister copper23 questions
Calculations on the metallurgy of copper21 questions
Origin and drilling of petroleum22 questions
Uses of urea21 questions
Ores, minerals and metallurgy22 questions
Review of the extraction of copper21 questions
Recovery of ammonia and recycling in the Solvay process21 questions
Sample questions: Chemical Industries
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. What is the reason, given in the introduction of the chapter, for the development of chemical industries?
A. The lack of mines in the world led to the closing of the industries making soaps
B. The discovery of petroleum in the world led to the end of the older industries
C. The shortage of water in the world led to the use of substitutes for natural fertilizers
D. The growing population and the wish for a better standard of living led to cheaper substitutes(correct answer)
Answer: D.The introduction says that the rapidly growing population and the desire to raise the standard of living forced scientists to devise cheaper substitutes for natural substances by chemical processes on a large scale.
Q2. What is metallurgy?
A. The art and science of making metals and alloys from their ores for practical use(correct answer)
B. The study of the rocks and mountains that are found in the crust of the earth
C. The process of making soaps and detergents from animal and vegetable fats
D. The science of the extraction of petroleum and gas from the rocks below the ground
Answer: A.The book defines metallurgy as the art and science of making metals and alloys from their ores with properties suitable for practical uses.
Q3. Which of the following is NOT a basic metallurgical operation according to the book?
A. Refining of the metal by electrolysis
B. Concentration of the ore by flotation
C. Fractional distillation of the crude ore(correct answer)
D. Roasting of the ore in a furnace
Answer: C.Fractional distillation is used for petroleum; the basic metallurgical operations are concentration, roasting, reduction and refining.
Q4. Why is the concentration of an ore carried out as the first operation, before roasting and reduction?
A. The mineral forms only a few percent of the mined material, so the useless matter is removed first(correct answer)
B. The ore must be refined by electrolysis before it can be roasted or reduced in a furnace
C. The ore must be dissolved in water before it can be crushed to a small size
D. The ore has to be made into an alloy before it can be roasted in a furnace
Answer: A.The mineral in a mined ore constitutes only a few percent; hence it is necessary to separate it from the useless material before the other operations.
Q5. Which step of metallurgy is described under the heading 'Roasting' in section 16.1.2?
A. Agitating the crushed ore with pine oil and water in a current of air
B. Heating the concentrated ore with silica and calcium carbonate in a blast furnace to form matte(correct answer)
C. Blowing air through molten copper sulphide in a converter to form blister copper
D. Dissolving the blister copper at the anode of an electrolytic tank
Answer: B.The book describes roasting as mixing the concentrate with silica and calcium carbonate and heating it in a blast furnace to get matte.
Q6. Why is blister copper unsuitable for electrical wires without further refining?
A. It is a gas at room temperature and so it cannot be drawn into wires
B. It is a compound of copper with silica and so it cannot conduct a current
C. It contains impurities such as silver and gold, which must be removed(correct answer)
D. It contains no copper at all but only iron and sulphur in the form of matte
Answer: C.Blister copper still contains silver, gold etc. as impurities, so it is refined by electrolysis (standard link with the next section).
Q7. Which of the following correctly matches the apparatus and the product in copper metallurgy?
A. Bessemer converter and anode mud
B. Flotation cell and blister copper
C. Blast furnace and matte(correct answer)
D. Electrolytic tank and froth
Answer: C.The blast furnace gives matte; the converter gives blister copper; the electrolytic tank gives pure copper and anode mud; the flotation cell gives the concentrate.
Q8. Urea is classified as which type of fertilizer?
A. Organic, being derived from the animals of the farm
B. Natural, being mined from the rocks of the earth
C. Biological, being made by the bacteria of the soil
D. Synthetic, being manufactured from NH₃ and CO₂(correct answer)
Answer: D.Urea is manufactured chemically from ammonia and carbon dioxide, so it is a synthetic fertilizer (the ammonia comes from natural gas, as noted in the box).
Q9. Why does an oil well often flow by itself at first and later require air pressure?
A. The rocks become non-porous with time, so they block the oil
B. The oil changes into gas with time, so it cannot be pumped any more
C. The natural gas pressure that pushes the oil out falls with time, so air is applied(correct answer)
D. The gas becomes heavier than the oil with time, so it sinks away
Answer: C.Initially gas pressure drives the oil out; if no gas pressure is present, air pressure must be applied (inference from the book's description).
Q10. Which of the following correctly matches the industry with its main product?
A. Electrolytic refining : urea
B. Solvay's process : sodium carbonate(correct answer)