OCR B Salters - F335 Exam - 15 June 2011

does ester hydrolysis require reflux?

does ester hydrolysis require reflux?

Esters can be hydrolysed with either an acid or an alkali, and both ways require the reaction to be performed under reflux.

what will be a model answer as to why there is a ring of delocalised electrons inside the benzene?

what will be a model answer as to why there is a ring of delocalised electrons inside the benzene?

Esters can be hydrolysed with either an acid or an alkali, and both ways require the reaction to be performed under reflux.

thats true

True

Hydrolysis of Esters
Hydrolysis is the breakdown of a molecule by water - it is the reverse of esterification. The hydrolysis of an ester can be carried out using an acid catalyst (such as sulphuric acid) or an alkili catalyst (such as sodium hydroxide). Alkaline hydrolysis is usually preferred because the reaction goes to completion.

what will be a model answer as to why there is a ring of delocalised electrons inside the benzene?

We need to know the experiments? E.g. outline acid-base titration, t.l.c, recrystallisation, colorimetry, refluxing, standard electrode potential, carrying out organic prep? G.l.C is the obvious one of course, unsure about there though

- Each Carbon atom in the ring has four delocalised electrons.- 3 of these electrons are involved in covalent bonding. (2 with the carbons next door in the ring and one hydrogen atom).
- One of the four electrons is not involved in bonding
- Theses electrons are evenly spread throughout the molecule forming a ring of delocalised electrons above and below the plane of the molecule.

Reflux is used the formation of Esters.


From the Exclusively endorsed Revision Guide

Noo, each carbon has four electrons in its outer shell, but all four are NOT delocalised.

Although the rest is right

I think we need to know about distillation and refluxing to as well as G.LC. Dont think we need to know the rest.

you sure?