# Experimentally proving the mechanism and rate laws of SN1 & SN2 reactions

I have been given the task of experimentally proving the rate laws and mechanisms of $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions. Unfortunately, the only equipment I can use is limited to analytical equipment that is needed to complete A-Level and IGCSE chemistry courses. So, I cannot use NMR machines, mass spectroscopy/spectrometry, etc.

It's obviously very easy to look at a nucleophilic reaction and see how fast it goes (using $\ce{AgNO3}$), but I do not know how I would go about quantifying this, i.e. actually numerically measuring the rate so that I can use the data I collect in a rate law equation.

Furthermore, I do not know how I would definitively prove the mechanism of $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions, through experiment. I originally, thought of measuring the rate of reactions with different primary, secondary and tertiary haloalkanes and try and use the rates I get to prove that they are undergoing $\mathrm{S_N1}$ or $\mathrm{S_N2}$, and go from there. But I don't think that would be deemed as definitive proof that what is going on is definitely, without a doubt, the exact $\mathrm{S_N1}$/$\mathrm{S_N2}$ mechanism.

• Can you please clarify what analytical equipment you can use? That significantly changes the possibility of the ways to address the question. – J M Sep 13 '16 at 20:36
• I did an experiment of this type using titration as an undergrad. Set up the reaction with varying concentrations of hydroxide nucleophile and halide. Titrated after a few methods and used the method of initial rates. – Ben Norris Sep 13 '16 at 20:40
• @JM Of course. I'm currently at a secondary school, doing A-Level and Further Chemistry and so the equipment I can use is any equipment in the Dept. Prep Room. This includes, all analytical equipment that is needed to complete A-Level and IGCSE chemistry courses. So, overall, not much I'm afraid. I'm sorry that I cannot be more specific than that; I would be able to elaborate more, after I have visited my Chemistry Department tomorrow, if you need more specifics. – Saul McShane Sep 13 '16 at 20:59