Identifying Acid and Base

[Daniel Jeon Dis-2A]

I don't understand how to look at a compound and tell if it is a base or an acid. In the question I was able to identify HCl and CH3COOH because I've seen it multiple times but for C6H5NH2 and CH3NH3CL, how am I able to tell that it is a base?

[Bailey Shioya 2D]

The compound C6H5NH2 can be identified as a weak base, as it contains one nitrogen atom with a lone pair. CH3NH3Cl, on the other hand, is an acid as CH3NH3+ as it is a proton donator once it is placed in water (it becomes dissociated).

[Alyssa_Miao_3B]

Gabriel told us in his workshop session that generally, acids contain H+ and -COOH, and bases contain OH- and N. Bases can also be identified as metals bound to oxygen molecules (ex: Li2O) and metals bound to OH- (ex: Ca(OH)2). Specifically for CH3NH3Cl however, you can tell that it is an acid since when you break the molecule down, you have CH3NH3+ and Cl-. Cl- is the conjugate base of the strong acid HCl. Therefore, you can deduce that CH3NH3 must be the conjugate acid of a weak base, since one molecule has to be the conjugate acid and the other must be the conjugate base. Hope this helps!