[a student]

hi
as you know we can use the isotope of hydrogen, duetrium, to find the mechanism of a reaction but it is difficult to use ¹³C as isotope of ¹²C to determine the reaction path and you have to use ¹¹C/¹⁴C  what is the reason H and D differ with only one notron so as ¹²C and ¹³C.
thanks.

[movies]

It is actually possible to do ¹²C/¹³C isotope effect experiments, but as you pointed out, these are rather difficult.

The key difference between H/D and heavier atom KIEs is that you must consider the percentage change in mass that comes from changing the isotope.  In H -> D this is a 100% increase in mass, but in ¹²C -> ¹³C the increase is only 8%!

[a student]

thanks alot I got my answer