Leaded petrol must not be used in a car fitted with a Pt-Rh catalytic converter. This is because

Alead deposits on the metal surface and blocks the active sites, poisoning the heterogeneous catalyst
Blead raises the activation energy of $2 NO + 2 CO N X_{2} + 2 CO X_{2}$ homogeneously in the gas phase
Clead oxidises Pt to a soluble +4 salt which dissolves in the exhaust
Dlead converts CO to $CO X_{2}$ so that the converter has nothing to do

Answer: A

The converter is a heterogeneous catalyst; its activity depends on free surface sites. Lead compounds from tetraethyllead adsorb irreversibly on Pt-Rh, which is catalyst poisoning. The reaction

2 NO + 2 CO N X_{2} + 2 CO X_{2}

is balanced and needs the clean surface to proceed.

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Leaded petrol must not be used in a car fitted with a Pt-Rh catalytic converter. This is because

Answer: A

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