Catalysts

What is a Catalyst?

A catalyst increases the rate of a reaction without being consumed in the process. It works by lowering the activation energy needed for the reaction.

Catalytic Converters

Catalytic converters in cars use catalysts to speed up the reaction of harmful gases:

• Nature of catalysts: Typically platinum, palladium, or rhodium.
• Reactions catalyzed:
  • Carbon monoxide is converted to carbon dioxide.
  • Nitrogen oxides are reduced to nitrogen and oxygen.
• Environmental benefits: Reduces harmful emissions and improves air quality.

Catalyst Poisons:

Substances like lead can poison catalysts by binding to their surfaces and reducing their effectiveness.

Activation Energy and Temperature

• Activation energy is the minimum energy required for a reaction to occur. Catalysts lower this barrier, allowing the reaction to proceed faster.
• As temperature increases, more particles have enough energy to overcome the activation energy, increasing the reaction rate.

Reaction Profile Diagrams:

• Without a catalyst: The activation energy is higher.
• With catalyst: The activation energy is lower, and the reaction occurs more easily.

Demonstrations

• Oxidation of Methanol: When methanol is exposed to a hot platinum wire, it oxidizes rapidly, demonstrating the effect of a catalyst.
• Oxidation of Potassium Sodium Tartrate: Adding cobalt(II) salts speeds up the decomposition of potassium sodium tartrate by hydrogen peroxide, demonstrating the effect of a catalyst.