caustic soda vs saline

caustic soda

noun
  • sodium hydroxide (NaOH), a strong alkaline substance used in the manufacture of paint, soap and detergents, or as a drain cleaner. 

saline

noun
  • Water containing dissolved salt. 

  • A salt spring; a place where salt water is collected in the earth. 

adj
  • Resembling salt. 

  • Containing salt; salty. 

How often have the words caustic soda and saline occurred in a corpus of books? (source: Google Ngram Viewer )