Question

A catalyst:
A .Changes $\Delta G$ for an equation
B. Acts by increasing the rate of the forward reaction more than the reverse reaction
C .Raise the equilibrium constant of a system
D. May have a molecular weight as low as 1 or higher than 200000

Answer 1

Hint:Catalysts are used in reactions to increase the rate of the reaction in the forward direction so more product is obtained. The process of adding a catalyst in the reaction is called catalysis. A catalyst does not alter any other thermodynamic properties such as free energy or any other properties related to it.

Complete step by step answer:
As we know the definition of catalyst is that they are the substance which is used in a chemical reaction to boost up the reaction rate by lowering the activation energy. And this process of increasing rate is called catalysis.
Catalysts are not consumed in the catalyzed reaction but can act repeatedly .Often very small amounts of catalyst are required. Catalysts are used when reaction rate is slow .For example, manganese dioxide or the enzyme peroxidase in organisms.
Generally chemical reactions occur faster in the presence of catalyst because the catalyst provides alternative pathway or mechanism
Gibbs energy depends upon the enthalpy of the reaction as well as on its entropy. Gibbs energy is state function dependent upon initial and final state of substance .Catalysts on the other hand are only present in the intermediate state of reaction .This implies that whether you use a catalyst or not changes of enthalpy will remain the same and hence the Gibbs energy will not be altered.
Catalyst equally increases the rate of forward reaction as the backward reaction.there by allowing the system to reach equilibrium faster .it is very important to keep in mind that the addition of a catalyst has no effect whatsoever on the final equilibrium position of the reaction .
Equilibrium constant does not change if we add a catalyst .The only thing that changes an equilibrium constant is change in temperature.The position of equilibrium does not change if you add a catalyst.
Catalysts may have molecular weight as low as 1nm or higher than 200000.
Hence, option D is the correct option.

Note:
Catalysts may or may not take part in the reaction but what is important to note is that a catalyst is never consumed during a reaction. In other words, if there is one mole of catalyst in the beginning of the reaction, there will be one mole of catalyst at the end of the reaction also. Regardless of how the reaction proceeds