What is the percent yield for Na plus Cl2 -- 2NaCl?

Answer 1

Percentage yield is given as:-

%yield = (mass of product obtained experimentally/theoretical yield)x100

where the theoretical yield is the maximum mass which could possibly be obtained assuming 100% stoichiometry.

So, say as an example if you start with 71g of Cl2 then:-

mol = mass/Mr Mr of Cl2 = 71

mol = 71/71

mol = 1 of Cl2

This is the limiting reagent, assuming we have at least 46g of sodium, thus we double this number as the reaction is 1:2

1 mole Cl2---->2moles NaCl

again we use:-

mole = mass/Mr Mr of NaCl = 58.5

2 x Mr = mass

2 x 58.5 = mass

maximum mass of NaCl possible = 117g

If the reaction is carried out and we achieve 100g of NaCl then:-

%yield = (100/117) x 100

= 85.5%