How can a positive catalyst alter the reaction?

A positive catalyst speeds up the rate of a chemical reaction by lowering the activation energy barriers. This enables a larger number of reactants to more easily bind to its active sites and get converted into the products, boosting the reaction yield and the reaction rate. 

For the reaction to occur, the reactants must come into contact with each other. A positive catalyst increases the surface area available for the reactants, allowing more molecules to come into contact and interact with each other. This increased contact between reactants allows the molecules to interact with each other more easily, raising the reaction rate and making the process more efficient.

Some of the more common positive catalysts that can speed up chemical reactions include oxygen, potassium, nitrogen, iron, sodium, phosphorus, and chlorine.