Dear leaner,

Actually yes,but they mostly prefer students with bsc chemistry , which probably you will concentrate on botany and related studies you don't get a chance to grab the msc in chemistry ,and don't have any kind of  practical work in chemistry ,which makes less eligible

Eligibility to obtain msc in chemistry one must complete /graduate degree in chemistry or allied chemistry with 50% or more secured

Most likely to join in chemistry field one must have pcm at 12th ,as most of bsc botany students are with pcb .

All the best.