when the balanced reaction equation is:
2HCl(aq) + Ca(OH)2(aq) → CaCl2(aq) + 2H2O(l)
from the balanced equation, we can get the molar ratio between HCl & Ca(OH)2
2:1
∴ the volume of Ca(OH)2 = 15.8 L HCl * 1.51 m HCl * (1mol Ca(OH)2/ 2mol HCl) * (1L ca(OH)2/0.585 mol Ca(OH)2
= 20.4 L