Question

The expensive metals used in catalytic converters of automobiles are-
A. Cadmium and Rhodium
B. Platinum, Palladium and Rhodium
C. Lead and Cadmium
D. Copper and Cadmium
E. Lead and Mercury

Answer 1

Hint: A catalytic converter is a large metal box placed right behind the engines in the automobile. Its main function is to control the emission of harmful substances in the automobile by performing basic redox reactions.

Complete answer:
A catalytic converter is a control device used in automobiles to reduce the number of pollutants they make. This exhaust emission control device uses reduction and oxidation reactions (redox) to convert toxic byproducts of combustion to less toxic substances. The engines of automobiles run on petroleum which is made from hydrocarbons. Whenever hydrocarbon fuels are burnt in the presence of oxygen(air), this leads to the release of carbon dioxide and water, and some pollutant gases.
The expensive metals used in this are Platinum, Palladium, and Rhodium which are used as catalysts. This device has two pipes coming out of it- the input pipe is connected to the engine and brings hot and polluted fumes from there while the output pipe is connected to the exhaust. The surface of the catalysts present are exposed, chemical reactions occur on them when engine fumes pass over the surface of these catalysts. Platinum is an active catalyst and used as a reduction as well as an oxidation catalyst. Rhodium is used as a reduction catalyst while Palladium is used as an oxidation catalyst. Chemical reactions occur on these catalysts that are present inside a honeycomb structure made from ceramic, and harmless gases are passed out from them that are released into the atmosphere from the automobile.

These metals used are rare, precious, expensive but have a broad range of applications and thus are often stolen from automobiles.

Option B: Platinum, Palladium, and Rhodium are the expensive metals used in the automobiles of catalytic converters. Therefore, this is the correct option.

All the other options are irrelevant.

Hence, the correct answer is option (B)

Note: The pollutant gases released from the catalytic converter are Carbon Monoxide (a poisonous gas), Volatile Organic compounds, and Nitrogen Oxide ( causes smog), sulfur dioxide, and the particulate matter that is the soot seen coming out from the vehicle. Few greenhouse gases are also emitted. These can cause various harmful diseases and can also increase the outside temperature.