The acid that results when a base accepts a proton is called

The order of decreasing basic strength of halides is:

Which of the following species are only Lewis acids but not Bronsted acids from $CO_{2}$,$BCl_{3}$,$NH_{3}$,$CH_{3}NH_{2}$,$NO_{2}^{+}$,and $C_{6}H_{5}NH_{3}^{+}$?

The conjugate base of ${(CH_3)_2}\mathop N\limits^ + {H_2}$ is:

Which of the following is the weakest Bronsted base?

Which of the following compounds can act as both a $Br\o nsted$ acid and a $Br\o nsted$ base?