Titration A quantitative experiment to determine the concentration of an acid or a base.

Let’s get started! Step #1 – Rinse one buret with base, it is 0.1M NaOH(aq). Rinse another buret with the acid, it has an unknown concentration.

Fill’er up Step #2 – Put the burets in a buret clamp and fill them just above 0.0ml.

Fill the tip. Step #3 – To fill the tip of the buret, drain a small amount of each into a flask and then pour it down the drain.

Take some data Step #4 – Record the value of each buret in your data table. Be sure to read the bottom of the meniscus.

Add some Acid Step #5 – Rinse the flask with distilled water and then dispense about 10ml of the unknown HCl(aq). Be sure to record the exact amount of HCl(aq) remaining in the buret. Read the bottom of the meniscus

Time for some indicator Step #6 – Add some phenolphthalein to the HCl(aq) in the flask. It should stay clear since phenolphthalein stays clear in an acid.

Titration time Add base to the flask until the solution turns pink. At this point, you will have neutralized the acid. This is called the equivalent point.

Equivalent Point

Data, let’s take a closer look NaOH(aq)HCl(aq) 0.1Munknown 7.5ml 10.0ml This is the data collected, how do we determine the concentration of the HCl(aq)?

Go to the MOLE!!! Use the molarity of the NaOH(aq) and the number of liters of NaOH(aq) to find the number of moles of NaOH(aq). x moles 0.1M = liters

Cross Multiply Baby When you cross multiply you now know that you used moles of NaOH. How many moles of HCl(aq) reacted with the moles of NaOH? HCl + NaOH  NaCl + HOH

Stoichiometry That’s correct, since there is a 1:1 ratio of HCl to NaOH, we know that moles of HCl reacted moles NaOH x 1 moles HCl 1 mole NaOH = moles HCl

What is the Concentration? Molarity = moles/liters moles HCl Molarity of HCl = liters HCl = 0.075M HCl(aq)