C. Johannesson

III. Titration/Neutralization18.4

III. Titration/Neutralization18.4

Ch. 18- Acids & BasesCh. 18- Acids & Bases

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A. NeutralizationA. Neutralization

ACID + BASE ACID + BASE SALT + WATER SALT + WATER

HCl + NaOH HCl + NaOH NaCl + H NaCl + H22OO

HCHC22HH33OO22 + NaOH + NaOH NaC NaC22HH33OO22 + H + H22OO

• Salts can be neutral, acidic, or basic.

• Neutralization does not mean pH = 7.

weak

strong strong

strong

neutral

basic

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B. TitrationB. Titration

TitrationTitration• Analytical method

in which a standard solution is used to determine the concentration of an unknown solution.

standard solution

unknown solution

C. Johannesson

Equivalence pointEquivalence point• Point at which equal amounts of

H3O+ and OH- have been added.

B. TitrationB. Titration

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Equivalence pointEquivalence point• Determined by…

• indicator color change–phenolpthalein turns hot pink in a base

B. TitrationB. Titration

C. Johannesson

Equivalence point Equivalence point • Determined by…

• dramatic change in pH

B. TitrationB. Titration

B. Titration and NeutralizationB. Titration and Neutralization

The solution of known concentration is called the standard solution

• added by using a buret Continue adding until the

indicator changes color

• called the “end point” of the titration

• end points are different for different indicators

B. Titration StepsB. Titration Steps

1. A measured volume of acid of known concentration is added to a flask

2. Several drops of an indicator are added

3. A base of unknown concentration is slowly added and swirled until the indicator changes color; measure the volume delivered by the buret

B. Titration ProcessB. Titration Process

C. Johannesson

C. Johannesson

B. TitrationB. Titration

moles H3O+ = moles OH-

MV n = MV n

M: MolarityV: volumen: # of H+ ions in the acid

or OH- ions in the base

C. Johannesson

B. TitrationB. Titration

42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4.

H3O+

M = ?V = 50.0 mLn = 2

OH-

M = 1.3MV = 42.5 mLn = 1

MV# = MV#M(50.0mL)(2)

=(1.3M)(42.5mL)(1)

M = 0.55M H2SO4

WorksheetWorksheet

Complete the worksheets on titration

C. Johannesson