A solution is made by dissolving 25.20 g of aluminum acetate in 185.0 mL of water. What is the concentration of acetate ions?

To answer this question, you need to know the aluminum acetate weight and formula. Molecular weight of aluminum acetate is 204.11g/mol, so the concentration should be: (25.20/204.11) / (0.185l) = 0.1234 mol/0.185l = 0.6673 M

The aluminum acetate Al (C2H3O2) 3 which mean for one aluminum acetate there will be 3 acetate ion. The concentration of acetate should be: 0.6673 M = 2M