Which is a feature of a single replacement reaction?

a. Substance XYZ breaks down into X and YZ.

b. Substance G reacts with compound XY to form GY and X.

c. Substance X burns rapidly in the presence of oxygen.

d. Substance QR and GT exchange ions with each other.

B. substance G react with compound XY to form GY and X

A single replacement reaction is where one atom of one of the reactants compounds leaves and other atom takes its place. This is represented by the equation AB + C - - - > AC + B, as you see in this representation the atom B leaves the compound AB and it is replaced by the atom C, forming the compound AC, while B stays alone. That is the same represented by the option b. Substance G reacts with compound XY fo form GY and X. So, option b. is the right answer.