c. Fill a buret or serological pipet with the titrating solution of known

concentration (Eq/L) and adjust the solution level until the bottom of the meniscus is at

zero.

d. Add the titrant from the buret or pipet dropwise to the solution being titrated.

It is extremely important to continuously swirl the titration reaction flask as the titrant is

added; this allows the specialist to observe the endpoint. If you have sufficient unknown

to perform the titration several times, it is recommended that you add the titrant quite

rapidly the first time to obtain a rough approximation of the endpoint. This will save a

considerable amount of time if several titrations have to be performed.

e. When the endpoint is reached (indicator changes color), record the volume of

titrant used by reading the bottom of the meniscus in the buret or pipet.

a. **Basic Rules for Solving Titration Problems**.

(1)

Three of the four values must be known.

(2)

The units of concentration MUST be Eq/L or mEq/L.

(3)

The units of volume and concentration must be the same respectively.

(4) It is crucial that the volume and concentration that relate to one another

are identified.

b. **Example 1**. It took 5.2 mL of a 0.10 Eq/L NaOH to titrate 5.0 mL of a HCl

solution. What is the mEq/L concentration of the acid?

Solution. Read the problem carefully and select the expression that will allow

you to solve the problem for the unknown quantity.

C1V1 = C2V2

Ensure that the concentration of the solutions are expressed in terms of their

normality and the units of volume are the same.

Substitute the given information into the appropriate expression.

C1V1 = C2V2

(0.10 Eq/L)(5.2 mL) = (C2)(5.0 mL)

MD0837

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