Correct answer:
C) Ca(OH)2
Note: The listed options in the question are incorrect. The accurate selections are shown below:
15. A total of 3.705 kg of substance Y is required to neutralize 100 moles of HCl(aq).
What might substance Y be? A Ca B CaO C Ca(OH)2 D CaCO3
Explanation:
A) Ca + 2HCl ---> CaCl2 + H2
Molar mass of Ca = 40 g/mol
The mass of Ca needed to neutralize 100 moles of HCl = 1/2 * 100 * 40 g = 2000g or 2 kg
B) CaO + 2HCl ---> CaCl2 + H2O
Molar mass of CaO = 56.1 g/mol
The mass of CaO needed to neutralize 100 moles of HCl = 1/2 * 100 * 56.1 g = 2805 g or 2.805 kg
C) Ca(OH)2 + 2HCl ---> CaCl2 + 2H2O
Molar mass of Ca(OH)2 = 74.1 g/mol
The mass of Ca(OH)2 necessary to neutralize 100 moles of HCl = 1/2 * 100 * 74.1 g = 3705 g or 3.705 kg
D) CaCO3 + 2HCl ---> CaCl2 + H2O + CO2
Molar mass of CaCO3 = 100 g/mol
The mass of CaCO3 required to neutralize 100 moles of HCl = 1/2 * 100 * 100 = 5000 g or 5.00 kg
Thus, the right choice is C.