Help! Titration and ester production.?

Question

How do I do titration properly, cos we didn't do well on that prac in class, it took too long, and we didn't get to finish.

Also, esters, can someone help me understand these?

Thanks in advance peoples.

Answer 1

Easy titration method:

one-half syringe full of base in T-tube with phenolphthalein; "titrate" rapidly with syringe of acid; if no end point reverse the process in another T-tube. This gives the approx amount of acid or base that you need to do the titration. Then run the titrant down to near the correct level and then do the "slow". No need to do the "slow" all the way down!!

Esters are the molecular (usually organic) "acid-base" reaction. The acid is acid and the base is alcohol. Ester and water are formed.

Answer 2

A titration is a volumetric method of determining the respective volumes of two reacting solutions so that sufficient of each is combined to reach a point of neutralisation. By knowing the concentration of one of the solutions, the concentration of the second solution can be calculated.

You therefore measure out an exact volume of the unknown concentration solution. A suitable indicator is added that will give a colour change at the neutralisation point. The solution of known concentration is added until the end point is reached.  You now have three known data and so the fourth can be calculated.

An ester is a chemical reaction that takes place between an alcohol and a carboxylic acid. The ester is formed and water is split off during the reaction. A classic example is the reaction between ethanol and ethanoic acid:

C2H5OH + HOOCH3C → C2H5OOCH3C + H2O I have deliberately written the acid CH3COOH backwards so that you can see where the water comes from. The reaction is carried out in the presence of concentrated sulphuric acid which acts as a dehydrating agent and removes the water, forcing the reaction in the direction of the products.