If 4.20 mol of calcium carbide (CaC2) reacts with an excess of water, how many moles of acetylene (C2H2), a gas used...

If 4.20 mol of calcium carbide (CaC₂) reacts with an excess of water, how many moles of acetylene (C₂H₂), a gas used in welding, will be produced?

CaC₂(s) + 2 H₂O(l)  Ca(OH)₂(aq) + C₂H₂(g)