- Decide which Hg salt you are going to use, maybe Hg(NO3)
- Estimate (I do not know how it can be done =p) the concentration of Hg in the unknown and prepare standards such that the concentration of the unknown falls withing the range of the calibration
- Then write an essay about no-brainer procedures that are natural to chemists and yet the people who wrote the exam papers are inane enough to ask for them