25 Answer: D Ease of C-Cl bond breaking Ethanoyl chloride is an acid chloride and hence the bond breaks the fastest, giving rise to the white ppt in the shortest amount of time. 26 Answer: D As question did not provide students with the pKa values of the different groups, they need to know that the generic pKa of the various groups. pKa: α -acid ~2- 3, α -amine ~9 R-acid ~4
H2 Chemistry 9647 2015 So at pH 11, all groups will have pH>pKa and be deprotonated. 27 Answer: D Approach to this question is to do the conversion on the functional group and count the number of atoms which have been lost or gained. Conversion from aldehyde to ketone not possible so B is out.
H2 Chemistry 9647 2015 28 Answer: C Recall the relative acidities of phenol and alcohols and their reaction with NaOH. Phenols will be deprotonated while alcohols will not. 29