Laboratory experiment, content of chemical it must establish (6,4)
I believe the answer is:
litmus test
'laboratory experiment content' is the definition.
I can't tell whether this defines the answer.
'of chemical it must establish' is the wordplay.
'of' says the answer is hidden in the clue.
'LITMUS TEST' is hidden in the letters of 'chemical it must establish'.
Can you help me to learn more?
(Other definitions for litmus test that I've seen before include "Observer may see red after one" , "Chemical trial" .)