Question 19 is a bitch of a question, but here is the answer straight from the solutions:
For 3 marks: Identifies at least TWO standard conditions and explains their necessity.
The standard conditions are: all solutions have a concentration of 1 mol/L; any gases have a pressure of 1 atm; the temperature is 25C; the comparison half-cell is a hydrogen half-cell. It is necessary to choose a standard set of conditions for an electrochemical reaction so that comparisons can be made and cell differences determined.