Organic Chemistry F. The Fuel

51. In which of the following types of heat engines carburetor is used? [U.P.P.C.S. (Pre) 2022]

(a) Steam engine
(b) Diesel engine
(c) Both diesel and petrol engines
(d) Petrol engine

Correct Answer: (d) Petrol engine

Solution:A carburetor is a device used by an internal combustion engine to control and mix air and fuel entering the engine. While the earlier versions of carburetors used to do this merely by allowing air to pass over the fuel surface, the advanced version of carburetors dispenses a metered amount of fuel into the stream of air to achieve this purpose. Since the 1990s, carburetors have been largely replaced by fuel injection for cars and trucks. However, carburetors are still used by some small engines (e.g., lawnmowers, generators, and concrete mixers) and motorcycles. Carburetors are only used in petrol engines. Diesel engines have always used fuel injection instead of carburetors.

52. Which of the following metals are used as catalysts in the catalytic converters to eliminate poisonous gases? [Chhattisgarh P.C.S. (Pre) 2023]

(a) Sodium
(b) Thorium
(c) Rhodium
(d) None of the above

Correct Answer: (c) Rhodium

Solution:Catalytic converters in automobiles typically use precious metals like platinum (Pt), palladium (Pd), and rhodium (Rh) as catalysts. These metals facilitate chemical reactions that convert harmful pollutants like carbon monoxide (CO), nitrogen oxides (NOx), and unburnt hydrocarbons into less harmful substances like carbon dioxide (CO₂), nitrogen (N₂), and water (H₂O). Rhodium is particularly effective in reducing nitrogen oxides.

53. Consider the following features of newer models of motor cars: [L.A.S. (Pre) 2000]

Radial tyres
Streamlined body
Multipoint fuel injection
Catalytic converter with exhaustWhich of these features make the new models of motor cars more fuel efficient?

(a) 1 and 2
(b) 2 and 3
(c) 2, 3 and 4
(d) 1, 3 and 4

Correct Answer: (b) 2 and 3

Solution:A streamlined design is one in which objects that move through a gas or liquid are shaped to match these lines and therefore reduce the energy required to produce that motion. Multi point fuel injection system injects fuel into individual cylinders based on commands from the on board engine management system computer—popularly known as the Engine Control Unit/ECU. These techniques result not only in better power balance amongst the cylinders but also in higher output from each one of them along with faster throttle response. The other two options radial tyres and catalytic converter with exhaust do not contribute to make the car more fuel efficient.

54. Hydrogen gas can be conveniently used as a fuel for running vehicles if it is absorbed at a very low temperature by a substance only to be released at the temperature generated by the exhaust. What is that substance found in India? [U.P.P.C.S. (Pre) 2008]

(a) Hydride
(b) Coals
(c) Soapstone
(d) Resins

Correct Answer: (a) Hydride

Solution:Hydrogen gas is absorbed by palladium hydride at very low temperature. It is used to power a range of new alternate fuel vehicles. Metal hydrides are compounds that can absorb and store hydrogen gas, typically under specific temperature and pressure conditions. When heated (for instance, by exhaust heat), they release the stored hydrogen, which can then be used as fuel. Research is ongoing to find efficient and cost-effective metal hydrides for hydrogen storage in vehicles.

55. Which of the following is the by-product derived from the refining process of petroleum? [U.P.U.D.A./L.D.A. (Pre) 2013]

(a) Petrol
(b) Charcoal
(c) Coal
(d) Asphalt

Correct Answer: (d) Asphalt

Solution:Petroleum refining is a complex process that separates crude oil into various fractions based on their boiling points. While petrol is a primary product, asphalt is a by-product of petroleum refining. Asphalt is also known as bitumen. It is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be refined from crude oil. The primary use of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other uses are for bituminous waterproofing products, including the production of roofing felt and for sealing flat roofs.

56. ‘Hydrocarbon Vision 2025’ is associated with: [U.P.P.C.S. (Pre) 2000]

(a) Storage of petroleum products
(b) Euro I and Euro II vehicles
(c) Green House effect
(d) None of the above

Correct Answer: (a) Storage of petroleum products

Solution:‘Hydrocarbon Vision 2025’ is associated with the storage of petroleum products and focuses on long-term energy security. It aims to ensure energy security by achieving self-reliance through increased indigenous production and investment in equity oil abroad.