How do you identify a limiting reactant?

What is the Identify the limiting reactant when 7.81 g of HCL reacts with 5.24 g of NaOH to produce NaCl and H 2 O?

• Answer:

  NaOH + HCl --> NaCl + H2O, so you need 1 mole of NaOH for each mole of HCl. To convert the weights of each reagent into the number of moles, you need to divide by the molar mass for that reagent. So, number of moles of HCl = 7.81/36.46 = 0.214 number of moles of NaOH = 5.24/40.00 = 0.131 and the HCl is in excess, and the NaOH the limiting reagent.