posted by ???? .
Something that isn't consumed by the reaction (so say A) is dissolved at the same time as something that is consumed by the reaction (B) in a solvent, so that they are in the same phase...what is this reaction an example of?
What is the most pervasive particle that is involved in an example of this type of reaction that isn't consumed by the reaction?
perhaps even 'homogeneous catalyst'.
But the question does not state the the material takes part in the reaction, it just 'isn't consumed', so it could be a non-reacting impurity, so that the reaction is a one phase homogeneous reaction where A is a non-reacting imputity.