Question

A supplier provides "Chemical A, 98%, for synthesis".
Another supplier provides "Chemical A,98%, Lab grade"
Are they equivalent?

Which is better for analytical use?
Thanks.

Answer 1

The truth is, each supplier has their own descriptions, and in those descriptions generally define the standard that they tested against. So without that, you have no idea what the other 2 percent is...is it a solvent, or trace other elements. So the question which is better for analytical use cannot be answered. I have never seen the word "for synthesis" on a label. Your teacher is leading you to compare with lab grade, which is sometimes useful for analytical purposes, but not always (depends on the use). So without a definition from the supplier, it is not possible to know.

Look at these two suppliers:
http://www.reagents.com/products/reagents/grades.html
http://secure.sciencecompany.com/Chemical-Grade-Designations-W53.aspx