Answer:
The answer to your question is letter A
Step-by-step explanation:
Process
1.- Calculate the molecular mass of AlCl₃
Al = 1 x 27 = 27
Cl = 3 x 35.5 = 106.5
AlCl₃ = 27 + 106.5 = 133.5
2.- Find the number of ions of Cl using proportions
133.5 grams of AlCl₃ ------------- 3 ions of Chlorine
400.5 grams of AlCl₃ ------------ x
x = (400.5 x 3) / 133.5
x = 9