Ions in Solutions (5A) Practice Test

A desalting step uses an anion-exchange resin in the OH$^-$ form. When a solution containing HCl passes through, exchange occurs: R–N$^+$(CH$_3$)$_3$ OH$^-$(s) + Cl$^-$(aq) $\rightleftharpoons$ R–N$^+$(CH$_3$)$_3$ Cl$^-$(s) + OH$^-$(aq). In the effluent, H$^+$(aq) + OH$^-$(aq) $\rightarrow$ H$_2$O(l). Which outcome would be expected from the described ion interaction?

A protein purification step uses a cation-exchange resin bearing fixed negative sulfonate groups (Resine). A sample in low-salt buffer contains Naba, Cababa, and a positively charged peptide Pba. The resin is initially in the Naba form. Ion exchange can be represented as: Resineb7Naba + Pba cc Resineb7Pba + Naba. Which outcome would be expected when the NaCl concentration in the buffer is increased substantially during elution?