Respuesta :

The reaction equation is:
CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂

Moles of CaC₂ = 32 / (40 + 12 x 2)
Moles of CaC₂ = 0.5

Molar ratio of CaC₂ to H₂O = 1 : 2
Moles of H₂O = 2 x 0.5 = 1 mole of H₂O needed