Determining a reaction can be a little difficult sometimes, especially in a case like youres, with more than one or two reactants. It's also hard to use you observations to predict anything:
the reaction is exothermic
In the second case, acid plus KOH is itself exothermic. So we can't be sure your observation describes the other reaction you're looking for.
and results in a slurry-mud like substance which turned into solid after sometimes.
This also, will depend more on how you mix things, than the real reaction. For example, a 100 ml of a 0.1 M concentration of each reactant, that forms a solid? It might, I don't know. Or are you mixing these reactants essentially pure, in just a bit of water to make a paste? Is that why you get a slurry? I assumed these were each in aqueous solution, or are you mixing them dry in a furnace of some sort?