Question

5. Ethanol has the formula `C_2H_6O`. Acetic acid has a similar formula of `C_2H_4O_2`. If there was a difference in your results for electrical conductivity of aqueous solutions for these compounds, how could this be explained?

Answer 1

Preferential ionisation of acetic acid in aqueous solution generates charged species able to conduct, whereas ethanol is far less likely to do this.

Explanation:

Acetic acid preferentially ionizes in aqueous solution due to the possibility to form a stable acetate anion.

One of the key reasons for its stability is the ability for acetate to exist as a delocalised resonance hybrid whereby the negative charge is effectively shared equally over the two oxygen atoms (the carbonyl oxygen as well as the one remaining when the -OH group loses its proton).

Ethanol, on the other hand, is not able to do this, and the electron donating effect of the `CH_3` group would destabilise the `CH_3CH_2O^-` ion, making its formation less favourable, and ionisation less likely.

So the preferential ionisation of the acetic acid means that charged species are favourably produced in solution, and are able to conduct electricity more so than with ethanol.