This question was not popular among the candidates and the performance of those who attempted it  was only fair.

In (a), candidates correctly distinguished between normal and acid salts and hygroscopic and deliquescent substances with correct examples.

In (b)(i), candidates could not correctly write the required balanced equation.  The expected answer from candidates were
           
I.  NaOH  +  H2SO4   →   NaHSO4   +  H2O 
II.  2NaOH  + H2SO4    +→   Na2SO4  +  2H2O

In (b)(ii), many candidates could not correctly calculate the volume of NaOH required for complete reaction with 20cm3 of H2SO4 to form a normal salt since they could not write the correct balanced chemical equation in (b)(i)(II).  The required answer to the question was as follows:

                              CB  VB    = 2
                              CA VA        1
since concentrations are the same 

                        VB  =   VA    x    2
                                  =  20 x 2
=40cm3               

In (c)(i) and (ii), candidates correctly listed the ions present in the electrolysis of CuCl(aq) as Cu2+,  H+,  OH-  and Cl- .They stated OH- and Cu2+ as the ions discharged at the anode and cathode respectively.

In (c)(iii), only few candidates, could correctly write the required equation for the reaction at each electrodes.  Expected answers from candidates were

I.Anode: 4OH-   →   2H2O   + O2   +  4e-
II. Cathode:    Cu2+   +  2e    →   Cu
In (c)(iv) – (v), majority of the candidates knew that aqueous HCl would be left after the electrolysis; blue litmus paper would turn red and any of extraction of metals/ purification of metals/ electroplating etc is an industrial use of electrolysis.