The Solvay process uses {HEAD ~ poisonous ammonia gas} with a complex column system to extract {TAIL ~ the said products} 
The Solvay process uses { HEAD ~ poisonous ammonia gas } with a complex column system to extract { TAIL ~ the said products }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL