In the reaction CaC_2(s) + 2H₂O ⟶ Ca(OH)_2(s) + C₂H_2(g), what is the mass of solid calcium needed to produce 1000cm³ acetylene gas at S.T.P?
[ C=2, Ca= 40, G.M.N =22400cm³]

• A.3.8g
• B.2.9g
• C.2.0g
• D.1.0g