1. The problem statement, all variables and given/known data One of the two pairs of reactants will undergo a reaction. Which one, and what are the products? Co(OH)2 (s) + NaOH (aq) ----> Al(OH)3 (s) + NaOH (aq) -----> 2. Relevant equations N/a 3. The attempt at a solution I thought it might have something to do with the reactivity series, but I'm not sure how to proceed.