Class 10 Chemistry Chapter 8 Important Question

• Important Multiple Choice Questions of Chapter Number 16: Chemical Industries of Chemistry class 10th Urdu Medium.
• Important Short Questions of Chapter Number 16: Chemical Industries of Chemistry class 10th Urdu Medium.
• (iii) Refining or purification of the metal: Refining the impure metal by electrolysis is the most widely used process of refining metals. For example, electrolytic refining of copper is carried out in an electrolytic tank having copper sulphate solution in it as shown in figure 16.6. Two electrodes; one of impure copper metal that acts as anode and the other of pure copper metal that acts as cathode are suspended in the electrolytic solution.
• MANUFACTURE OF SODIUM CARBONATE BY SOLVAY’S PROCESS: Principle of Solvay’s process lies in the low solubility of sodium bicarbonate at low temperature i.e. at 15°C. When CO2 is passed through an ammonical solution of NaCl called ammonical brine only NaHCO3(s) precipitates.
• Raw Materials: The raw materials needed for this process are cheap and easily available. They are in abundance, such as, (i) Sodium chloride (NaCl) or brine. (ii) Limestone (CaCO3). (iii) Ammonia gas (NH3).  
• Basic Reactions: The process consists of the following steps:
• (i) Preparation of ammonical brine:
• First of all, ammonical brine is prepared by dissolving ammonia gas in sodium chloride solution (brine).
• (ii) Carbonation of ammonical brine: Ammonical brine is fed into carbonating tower and carbon dioxide is passed through it. Following reactions take place in the carbonating tower. The temperature of the mixture is lowered to 15°C and precipitates of NaHCO3 are obtained.
• Advantages of Solvay’s process: (i) It is a cheap process as raw materials are available at very low prices. (ii) Carbon dioxide and ammonia are recovered and reused. (iii) Process is pollution free, because the only waste is calcium chloride solution. (iv) Sodium carbonate of very high purity is obtained. (v) Consumption of fuel is very less since no solution is to be evaporated. 
• PETROLEUM INDUSTRY:  Petroleum Petroleum is a natural product found under the Earth’s crust trapped in rocks. Petroleum means rock oil. It is a complex mixture of several gaseous, liquid and solid hydrocarbons having water, salts and earth particles with it. It is lighter than water and is insoluble in it.
• Origin of Petroleum: Petroleum was formed by the decomposition of dead plants and animals buried under Earth’s crust millions of years ago. It is believed that millions of years ago living plants and animals in the seas died. Their bodies sank and buried under mud and sand. 
• The crude oil is refined in the refineries. Refining process is the separation of crude oil mixture into various useful products (fractions). It is carried out by a process called fractional distillation. The principle of fractional distillation is based upon separation of substances depending upon their boiling points. The substances having low boiling points boil out first, leaving behind others. Then next fraction of slightly higher boiling point boils out.
• Define concentration process used in metallurgy of copper.
• Why a small amount of coke is required in the smelting process? How is slag formed during smelting.
• Why is lime added in the smelting process?
• How are slag and matte removed from the blast furnace?
• What is difference between slag and matte?
• Mention the chemical reactions for the formation of metallic copper in the bessemerization process.
• What is blister copper?
• Why anode is eaten up in electrorefining process?
• What do you mean by anode mud?
• Why only NaHCO3 precipitates, when CO2 is passed through the ammonical brine?
• Which raw materials are required for the formation of sodium carbonate?
• How is CO2 prepared in the Solvay’s process?
• Give the reaction of formation of ammonia in the process.
• Give the advantages of Solvay’s process.