Question

A chemist needs to determine the concentration of a sulfuric acid solution by titration with a standard sodium hydroxide solution. He has a 0.1294 M0.1294 M standard sodium hydroxide solution. He takes a 25.00 mL25.00 mL sample of the original acid solution and dilutes it to 250.0 mL.250.0 mL. Then, he takes a 10.00 mL10.00 mL sample of the dilute acid solution and titrates it with the standard solution. The endpoint was reached after the addition of 17.43 mL17.43 mL of the standard solution. What is the concentration of the original sulfuric acid solution?

Answer 1

H₂SO₄ + 2NaOH = Na₂SO₄ + 2H20

USING M1V1=M2V2,

M1 = X (TO BE CALCULATED)

V1 = 25ML

V2 = 250 ML

M2 = M1V1/V2

M2 = X*25/250

M2 = 0.1X

CONCENTRATION OF H₂SO₄ AFTER DILUTION IS 0.1X

GIVEN CONC. OF NaOH = 0.1294 M

NOW TITRATING THE SULPHURIC ACID WITH 0.1294M NaOH, END POINT REACHED AFTER USING 17.43 ML OF NaOH

M1 = 0.1X

M2 = 0.1294 M

V1 = 10 ML

V2 = 17.43 ML

AGAIN USING, M1V1 = M2V2

0.1X x 10 = 0.1294 x 17.43

X = 0.1294 x 17.43

= 2.255 M

THE CONCENTRATION OF THE ORIGINAL SULPHURIC ACID IS 2.255 M