Answer: 65.38g of Ca(OH)2 is needed
Explanation:
From The equation of reaction
2 HCl + Ca ( OH ) 2 ⟶ CaCl 2 + 2 H 2 O
NB: Molar mass of HCl= 1+35.5=36.5
Ca(OH)2= 74
From The stoichiometric equation
2mol of HCl(36.5×2=73) require 1mol of Ca(OH)2 (74g)
Hence 64.5g of HCl will require 64.5×74/73= 65.38g of Ca(OH)2