The percent yield is 83.12%
calculation
percent yield = actual yield / theoretical yield x 100
actual yield =125.1 g
Theoretical yield is calculated as below
Step 1: find the moles of MgCl₂
moles = mass÷ molar mass
from periodic table the molar mass of mgCl₂ =24.3 +(35.5 x2) =95.3 g/mol
moles = 50.0 g÷ 95.3 g/mol =0.525 moles
Step 2: use the mole ratio to determine the moles of AgCl
from given equation MgCl₂: AgCl is 1:2
therefore the moles of AgCl = 0.525 x2/1 =1.05 moles
Step 3: find the theoretical mass AgCl
mass = moles x molar mass
from periodic table the molar mass of Agcl = 107.87 +35.5 =143.37 g/mol
mass = 1.05 moles x 143.37 g/mol =150.5 grams
The percent yield is therefore = (125.1 g/150.5) x 100 = 83.12%