Industrial Chemistry — Set 3
Chemistry · औद्योगिक रसायन · Questions 21–30 of 40
Which metal is the best conductor of electricity?
Correct Answer: D. Silver
Silver has the highest electrical conductivity of all elements. Copper is more commonly used in wiring because it is much cheaper than silver. Gold is used in specialized electronics because it does not tarnish.
Which gas is used for the artificial ripening of green fruits?
Correct Answer: B. Ethylene
Ethylene is a natural plant hormone that triggers the ripening process. In industrial practice, it is applied in controlled rooms to ripen fruits like bananas. Acetylene is sometimes used as a substitute but is often restricted.
What is the primary constituent of 'LPG' (Liquefied Petroleum Gas)?
Correct Answer: C. Butane
Butane is the main component of the gas used in household cooking cylinders. It is easily liquefied under pressure for convenient storage and transport. A strong-smelling agent like ethyl mercaptan is added to detect leaks.
Which of the following is an alloy of Copper and Tin?
Correct Answer: B. Bronze
Bronze is primarily composed of copper with about 12% tin. It is harder than pure copper and was historically used for making tools and statues. Brass, on the other hand, is an alloy of copper and zinc.
Which chemical is known as 'Oil of Vitriol'?
Correct Answer: B. Sulfuric acid
Sulfuric acid was historically called oil of vitriol because of its oily appearance. It is a highly corrosive mineral acid produced industrially by the Contact process. It is used in almost every branch of industrial chemistry.
Which gas is evolved when washing soda is treated with hydrochloric acid?
Correct Answer: C. Carbon dioxide
The reaction between a carbonate and an acid always produces carbon dioxide gas. This gas can be identified because it turns lime water milky. Washing soda is chemically known as sodium carbonate.
What is the common name for 'Calcium Sulfate Hemihydrate'?
Correct Answer: B. Plaster of Paris
Plaster of Paris is formed by heating gypsum to a specific temperature. It is widely used in construction, medicine, and for making decorative casts. It hardens quickly when mixed with a small amount of water.
Which non-metal is the only one that exists in liquid state at room temperature?
Correct Answer: B. Bromine
Bromine is a reddish-brown liquid with a sharp, choking smell. While mercury is a liquid metal, bromine is the only liquid non-metal. It is used in the manufacture of flame retardants and dyes.
Which acid is present in 'Vinegar'?
Correct Answer: A. Acetic acid
Acetic acid gives vinegar its characteristic sour taste and pungent smell. A dilute solution of about 5-8% acetic acid is commonly used as a preservative. It is produced industrially by the fermentation of ethanol.
Which substance is used to remove the permanent hardness of water?
Correct Answer: D. Washing soda
Washing soda reacts with soluble calcium and magnesium salts to form insoluble precipitates. This process removes the ions responsible for the hardness of the water. It is a standard chemical treatment in domestic and industrial laundries.