Answer:
15 mol Mn(OH)2
Explanation:
The first step when given a chemical reaction is to balance it. That means there are equal moles of Mn on the reactant side [left] as on the product side [right]. In this case we have manganese hydroxide reacting with aluminum, which is a displacement reaction. So the ff is the balanced reaction:
3 Mn(OH)2 + 2 AI → 2 Al(OH)3 + 3 Mn
Now, get the ratio of how many moles of Mn(OH)2 per moles of Al2O3. The answer is 3:2. That means you need 15 moles of Mn(OH)2
3/2 = x/10
x = 15
