Which of the following is Lewis base: AlCl3, CO, CO2, or BF3? Organic Chemistry Acids and Bases Main Characterstics or Lewis/Bronsted Definition 1 Answer Owen Bell Dec 28, 2015 #"CO"# Explanation: #"AlCl"_3# , #"BF"_3# , and #"CO"_2# are Lewis acids, as they accept a pair of electrons from another species during the formation of a co-ordinate bond. Therefore, the Lewis base here is #"CO"#. Answer link Related questions How can I complete the following equation: #CH_3CH_2NH-CH_3 + HBr ->?# Which definition for acids and bases is the right one: Lewis or Brønsted? How does Lewis define acids and bases? What definition of acids and bases emphasizes the role of protons? How are acids and bases defined by Brønsted theory? How did Lewis create his acids and bases model? What are the differences between Brønsted–Lowry model and the Lewis model for acids and bases? How is #H^+# acting in the reaction #H^++:NH_3 ->[H:NH_3]^+#according to the Lewis definition? How is #NH_3 # acting in the reaction #H^++:NH_3 ->[H:NH_3]^+#according to the Lewis definition? Which pair is a Brønsted–Lowry conjugate acid–base pair? #NH_3 ; NH_4^+# or #H_3O^+ ; OH^-#... See all questions in Main Characterstics or Lewis/Bronsted Definition Impact of this question 10912 views around the world You can reuse this answer Creative Commons License