Additives rhymes with:
alternatives, conservatives, conservatives', cooperatives, derivatives, executive's, executives, executives', expletives, fixatives, imperatives, initiatives, laxatives, narratives, negatives, neoconservatives, operatives, palliatives, performatives, positives, prerogatives, preservatives, preventatives, relative's, relatives, representative's, representatives, representatives', superlatives
Additives sounds like:
adapso, adipose, adobe's, advice, advise, advises, advocacy, attaboys, audiotapes, audiovox, autopsies, autopsy