Few reactions are produced by this remarkable talk (4,3)
I believe the answer is:
rare gas
'few reactions are' is the definition.
The definition suggests a singular noun which matches the answer.
'by this remarkable talk' is the wordplay.
'by' says to put letters next to each other.
'this remarkable' becomes 'rare' (I've seen this in another clue).
'talk' becomes 'gas' (gas can mean to chat).
'rare' next to 'gas' is 'RARE GAS'.
'produced' is the link.
Can you help me to learn more?
(Other definitions for rare gas that I've seen before include "Element such as helium, neon etc" , "Such as neon, argon, etc" , "Eg, helium or neon" , "Such as argon or xenon" .)