Question

Vinegar is an aqueous solution of acetic acid (CH3COOH) that can be made from any source containing starch or sugar. Apple cider vinegar is made from apple juice that is fermented to produce alcohol which then reacts with oxygen in the air in the presence of certain bacteria to produce vinegar. Commercial vinegar must contain no less than 4 grams of acetic acid per 100 mL of vinegar. Suppose the titration of a 25.00 mL sample of vinegar requires 11.20 mL of a 5.95 M solution of NaOH. What is the molarity of the vinegar? Could this be a commercial sample of vinegar?

Answer 1

moles of NaOH(aq),

n(NaOH)moles = c x V

volume of NaOH(aq) = v(NaOH) = 0.0112 L
concentration of NaOH(aq) = c(NaOH) = 5.95 mol L-1

moles NaOH(aq) = c(NaOH) × V(NaOH)
                             = 0.0112 *5.95 = 0.06664 mol

n(acid) = n(base)
n(CH₃COOH) = n(NaOH)
                    1 = 1

1 mole of NaOH neutralises 1 mole of CH₃COOH
therefore 0.06664 moles of NaOH neutralises 0.06664 moles of CH₃COOH
moles of acetic acid = n(CH₃COOH) = 0.06664 mol

volume of acetic acid solution (vinegar) = v(CH₃COOH) = 0.02500 L
concentration of acetic acid solution (vinegar) = n(CH₃COOH) ÷ v(CH₃COOH)
c(CH₃COOH) = 0.06664 ÷ 0.02500 = 2.6656 mol L^-1

Yes, this Could be a commercial sample of vinegar.