What would be the molarity of a solution made from 86.5 g Ca (OH) 2in 200.0 ml of water?

5.84 M

Explanation:

First you have to convert grams of Ca (OH) 2 to moles,

since molar mass is 74.093 g/mol, we divide the amount you have by the molar mass: (86.5 g) / (74.093 g/mol) = 1.1675 moles of Ca (OH) 2

Then, knowing molarity is (moles / volume in liters), we have to convert 200 mL to liters, which is 0.200 L

Putting it together, molarity = (1.1675/0.200) M = 5.84 M