Select all correct statements about a catalyst.

AIt accelerates the forward and reverse reactions of a reversible reaction by the same factor.
BIt does not alter the standard Gibbs energy change $Δ G^{\circ}$ of the reaction.
CIt changes the enthalpy change $Δ H$ of the reaction.
DIt can be recovered chemically unchanged at the end of the reaction.

Answer: A, B, D

A catalyst lowers

E_{a}

in both directions equally and leaves

Δ H

Δ G^{\circ}

and

K

unchanged. It is not consumed overall. So A, B and D are correct and C is wrong.