Neutralization & Titration

Lynette Shao

Neutralization

Acids release H+ ions into solutions and bases release OH- ions.

Mixing the two solutions would cause H+ and OH- to combine and make H2O (plain water).

Neutralization will always produce water and salt.

Example: HCl + NaOH -> H2O + NaCl

Practice Problems

Write balanced equations for the following neutralization reactions: 1. Hydrochloric acid (HCl) with

Aluminum Hydroxide (Al(OH)3)

2. Sulfuric Acid (H2SO4) with Magnesium Hydroxide (Mg(OH)2)

Answers:

1. 3HCl + Al(OH)3 -> AlCl3 + 3H2O 3H+ + 3OH- -> 3H2O

2. H2SO4 + Mg(OH)2 -> MgSO4 + 2H2O 3H+ + 3OH- -> 3H2O

Titration

Method used in chemistry that relies on the neutralization reactions of acids and bases.

Process used to determine the concentration of an acid or a base.

Phenolphthalein Colorless in acids. Pink in bases. Used to determine neutralization. When adding an acid to a basic solution,

the color will remain pink for some time until you reach the point where the acid exactly neutralizes the base. (light pink)

One more drop of acid would turn the solution colorless.

Titration Video

http://www.youtube.com/watch?v=Y-5QJIr7Xm4

What the video did not include

Carefully rinse all equipment with tap water. For the burette, be sure to rinse out the tip and sides. For the pipette, be sure to rotate the filler as you dump the water.

Rinse the burette with base the same way as you did with water.

Fill the burette with the base and allow a small amount to run through until the meniscus is on a line.

Record the initial and final volume of the base in the burette to 2 decimal places.

Calculating the concentration of an unknown

Using the results of your titration, you can calculate the concentration of an unknown.

Remember to use the concordant value. Sample question:

A Solution containing sodium hydroxide requires 15.5 ml of 0.15M hydrochloric acid to reach equivalence. If the volume of the sodium hydroxide is 1.5 liters, what is the concentration of the sodium hydroxide solution?

Practice problems:

If 14.7 ml of 0.102M NaOH is required to titrate 25.00 ml of HCl solution, what is the molarity of the hydrochloric acid solution?

If 19.1 ml of 0.118M HCl is required to neutralize 25.00 ml of a sodium hydroxide solution, what is the molarity of the sodium hydroxide?

THE END