2Na + 2H2O --->2 NaOH + H2
Molar mass of Na= 23 gm
Mass of Na= 8.21 gm
number of moles of Na = mass /molar mass
                                  Â
= 8.21/23
                                Â
=0.357 mol
Molar mass of water = 18 gm
mass of water = 6.98 gm
number of moles of water = mass / molar
mass
                                      Â
= 6.98/18
                                     Â
=0.388 mol
From reaction given 2 mol of Na requires 2 mol of
water
Na available is 0.357 mol whereas water available is
0.388 mol
Clearly Na (sodium) is limiting reagent
