This question is incomplete, the complete question is;
In recrystallization from boiling water of benzoic acid contaminated with acetanilide, you begin with an impure sample of 5 grams. If the % composition of the acetanilide impurity in the sample is 6.3 %, what is the minimum amount in mL of solvent (water) required for the recrystallization
Compound Solubility in water at 25°C Solubility in water at 100°C
Benzoic Acid 0.34 g/100mL 5.6 g/100mL
Acetanilide 0.53 g/100mL 5.5 g/100mL
Answer:
The minimum amount in mL of solvent (water) required for the recrystallization is 91 mL
Explanation:
Given the data in the question;
mass of sample = 5 g
percentage composition of the acetanilide impurity = 6.3%
mass of the acetanilide in impure sample will be;
⇒ 6.3% × 5 g = 0.315 g
Mass of benzoic acid in impure sample;
⇒ 5 g - 0.315 g = 4.685 g
now, solubility in water at 100°C for benzoic acid = 5.6 g/100mL
hence 4.685 g of benzoic acid is soluble in x mL
x = [ 100 mL × 4.685 g ] / 5.6 g
x = 83.66 ≈ 84 mL
Also, solubility in water at 100°C for acetanilide = 5.5 g/100mL
hence 0.315 g of benzoic acid is soluble in x mL
x = [ 100 mL × 0.315 g ] / 5.5 g
x = 5.727 ≈ 6 mL
So, the minimum amount in mL of solvent (water) required for the recrystallization will be;
⇒ 85 mL + 6 mL = 91 mL
The minimum amount in mL of solvent (water) required for the recrystallization is 91 mL
