For this lab the main idea was to titrate the NaOH and then the vinegar to determine the Moralities of both. To titrate, we used KHP and the indicator phenolphthalein and added NaOH till the solution was a faint pink. When the solution turns faint pink, we know that all of the H+ has been used in the reaction.
The process itself was really tedious because we had to drop the NaOH slowly and make sure we got the exact point where the solution turned a faint pink. If the solution becomes a bright pink, that means we already missed the point of equilibrium. Even adding one drop past the light pink point turns the solution extremely pink so it is important to watch carefully. (Example of bright pink to the right and faint pink above)
Since this lab was based on percent error, it was important to do many trials so we would average to as close to the correct answer as possible. The first time we did it we got an extremely high percent error and that freaked us out and we were determined to be more precise for our next few trials.
This lab was a little stressful in that we had to be so exact, but it was so rewarding in the end when you know you got that perfect titration! The bright pink always stressed me out too.
ReplyDelete