Acetylene can be prepared from calcium carbonate by a series of reactions. The mass of 80% calcium carbonate required to prepare 2 moles of acetylene is

The sequence of reactions involved areCaCO3 → CaO + CO2 ...(1)CaO + 3C → CaC2 + CO ...(2)CaC2 + 2H2O → C2H2 + Ca(OH)2 ...(3)GivenMoles of C2H2 formed = 2molesstarting from (3) equationCaC2 +2H2O→C2H2 +Ca(OH)2  1 mole of CaC2 -1 mole of C2H2 x1 moles of CaC2 -2 moles of C2H2X1 = 2moles2equationCaO+3C→CaC2 +CO 1 mole of CaO -1 molof CaC2 X2 moles of CaO -2 moles of CaC2X2 = 2moles1st equationCaCO3 →CaO +CO2 1 mole of CaCO3 -1 mole of CaO X3 mole of CaCO3 -X3 mole of CaOX3 = 2molesWeight of pure CaCO3 required =2×100 =200 gmWeight of 80% pure CaCO3 required =200×10080= 250g