How do you determine a limiting or excess reagent

Determine the mol ratio of both the reagents

Then calculate the mol for both reagents

eg NaOH + HCl - - > NaCl + H2O

given in qns NaOH is 5g and 50cm^3 of 0.2mol/dm^3 HCL

from eqn:

Mole ratio of NaOH to HCL = 1:1

from calculations:

no. of mole of NaOH = 5 / (23+16 + 1) = 0.125mol (excess)

no. of mole of HCL = 0.2 * 50/1000 = 0.01 mol (limiting)

NaOH : HCL should equals to 1:1 however from calculations it is not 1:1 and n (HCL) < n (NaOH) HCL limiting, NaOH excess