Q1: Catalyst used in the catalytic converter employed in automobiles to convert CO into CO and for complete oxidation of un-burnt hydrocarbons is

ANS:D - platinum

Platinum is a precious metal that is highly valued for its remarkable physical and chemical properties. It is a dense, malleable, and ductile metal with a silvery-white appearance. Platinum is extraordinarily resistant to corrosion, oxidation, and tarnishing, making it highly durable and suitable for various applications, including industrial, automotive, jewelry, and electronic sectors. In the context of catalytic converters in automobiles, platinum plays a crucial role as a catalyst. A catalyst is a substance that accelerates a chemical reaction without being consumed in the process. In catalytic converters, platinum facilitates the conversion of harmful pollutants in the exhaust gases of internal combustion engines into less harmful substances through a series of chemical reactions. Specifically, platinum serves as a catalyst for several key reactions:

1. Oxidation of Carbon Monoxide (CO): Platinum facilitates the conversion of carbon monoxide (CO), a toxic gas, into carbon dioxide (CO2), which is less harmful to the environment. The reaction is as follows: 2CO+O2​→2CO2​
2. Oxidation of Hydrocarbons (HC): Unburned hydrocarbons (HC) present in the exhaust gases are also oxidized by platinum, converting them into carbon dioxide (CO2) and water vapor (H2O).
3. Reduction of Nitrogen Oxides (NOx): While platinum itself is not directly involved in this reaction, it works in conjunction with other metals like rhodium and palladium to reduce nitrogen oxides (NOx) to nitrogen (N2) and oxygen (O2) through a process called selective catalytic reduction (SCR).

The high surface area of platinum catalysts, often in the form of finely dispersed particles on a ceramic or metallic substrate, provides ample active sites for these chemical reactions to occur. The catalytic converter effectively transforms harmful emissions into less harmful ones, contributing to cleaner air and reduced environmental impact from vehicle exhaust. Overall, platinum's exceptional catalytic properties, combined with its resistance to high temperatures and corrosive environments, make it an indispensable component in automotive catalytic converters, playing a vital role in reducing air pollution and improving air quality.