Summary
Highlights
This video covers the procedure for carrying out a titration, a required practical for triple chemistry. A titration helps determine the concentration of an acid by neutralizing it with a known volume and concentration of alkali.
First, use a pipette to transfer 25 cm cubed of sodium hydroxide solution into a conical flask. The conical flask minimizes splashing. When using a pipette, allow the liquid to drain naturally rather than blowing it out, as this can affect volume accuracy.
Fill a burette with sulfuric acid. Slowly add the acid drop by drop to the alkali, swirling the solution to ensure mixing, until the solution is neutral. If using methyl orange, the color change will be from yellow to permanently red.
Read the volume of acid added from the burette by ensuring your eye is level with the bottom of the meniscus. Titrations should be repeated multiple times until two readings are within 0.1 cm cubed, and then the mean of these readings is calculated for the final volume.
With the known volume and concentration of the alkali, and the volume of acid needed for neutralization, the concentration of the acid can be calculated. The next video will cover these calculations.
Next, add five drops of an indicator, such as methyl orange or phenolphthalein, to the alkali in the conical flask. Place the flask on a white tile to clearly observe the color change.