Answer:
70.82%
Step-by-step explanation:
Recall that: mole = mass/molar mass
From the equation of the reaction;

2 moles of aluminium gives 2 moles of AlCl3
58/26.98 moles of aluminium will give x/133.34 moles of AlCl3
x = 2.1497 x 133.34
= 286.64 g
58 grams of aluminium is supposed to yield 286.64 grams of aluminium chloride. If 203 grams of AlCl3 was produced,
Percentage yield = 203/286.64 x 100%
= 70.82%
The percentage of the reaction is 70.82%