Answer: 4.36%
Explanation:
Here is the complete question:
Calculate the percent acetic acid in vinegar when a 30.84cm^3 volume of 0.128 M NaOH is required to reach the phenolphthalein endpoint in the titration of a 5.441g sample of vinegar.(molar mass of vinegar is 60.05g/mol)
moles NaOH = 0.03084 dm^3 x 0.128
M=0.00395
mass acetic acid = 0.00395 mol x 60.05 g/mol=0.237 g
Percentage of acetic acid:
= 0.237 x 100/ 5.441
= 23.7/5.441
= 4.36%