The rate of reaction between 2-chloro-2-methylpropane, (CH₃)₃CCl, and methanol is investigated. When a large excess of methanol is used, the overall reaction is first order. (CH₃)₃CCl + CH₃OH → (CH₃)₃COCH₃ + HCl Fig. 3.1 shows the results obtained. [Figure 3.1] (c) (i) Define standard electrode potential, E®. (ii) A salt bridge is used in an electrochemical cell. State the function of the salt bridge. Explain your answer. (iii) Complete the diagram of the apparatus that can be used to measure the Eº of the Cr2O72-(aq), H+(aq)/Cr3+(aq) electrode against the standard hydrogen electrode. Your diagram should be fully labelled to identify all apparatus, substances and conditions. [Figure with salt bridge] (iv) The E® of the Cr2O72-(aq), H+(aq)/Cr³+(aq) electrode is +1.33V. Label the negative electrode and the direction of electron flow in the external circuit when the current flows in your diagram in (c)(iii). (d) Table 3.1 lists relevant electrode potentials for some electrode reactions for use in (d)(i) and (d)(ii). Table 3.1 electrode reaction E/V Cr2O72- + 14H+ + 6e¯ = 2Cr3+ + 7H2O +1.33 CH3CHO + 2H+ + 2e¯ = CH3CH2OH -0.61 CH3COOH + 2H+ + 2e¯ = CH3CHO + H₂O -0.94 O2 + 4H+ + 4e¯ ⇌ 2H₂O +1.23