2nd Order Reaction - Units of Volume is in molarity?

[laser1]

TL;DR

This experiment investigates the reaction order of iodide ion oxidation by persulphate ion. Confusion about units in lab manual.

This experiment investigates the reaction order of iodide ion oxidation by persulphate ion. The above image is my pre lab manual. Are the two equations boxed in blue valid? This seems to imply that that the units of [A] is the same as the units of V. But units of concentration being equal to the units of volume?? According to my lab demonstrator, the units of V in this case is in mol/L, which I haven't seen before for a unit of volume. V is also the titre value, which is from the titration - units of volume should be in mL/L etc. in my opinion.

Can someone please provide some insight on this? I can provide more details about the lab if needed. Thanks!

 

[mjc123]

You are right that there is an inconsistency; if you use the two equations to analyse your results, you will get different values of k₂, with different units. As the text says, [A] is proportional to V, so you need to know the constant of proportionality. If [A] = qV, then the second equation needs to have 1/qV_∞ instead of 1/V_∞. (The second term on the RHS is a ratio, and q will cancel out.)