Question: At which laboratory was Carsten Olsen employed as an assistant to the Danish chemist who introduced the concept of pH?
Facts:
Carsten Olsen was a Danish plant ecologist and plant physiologist
Carsten Olsen was employed by the Carlsberg Laboratory as assistant to S. P. L. Sørensen
S. P. L. Sørensen is a Danish chemist
Answer: Carlsberg Laboratory