Hcl is a stronger acid than the ammonium ion (nh4+). which one of the following is true?

a) equilibrium constant for hydrolysis of hcl is smaller than that for nh4+
b) cl- is a weaker base than nh3
c) solutions of hcl will always have more hydrogen ions than solutions of nh3
d) ph of 0.1moll-1 solution of hcl will be greater than the ph of a 0.1 moll-1 solution of nh3

the answer is b, but could someone explain it to me? i though cl- was neutral, not basic?

The chloride ion is a weak conjugate base of a strong acid that is hydrochloric acid.

Explanation:

Weak conjugate bases are produced from strong acids, and strong conjugate bases are produced from weak acids.  Here hydrochloric acid is a strong acid, and when dissolved into water, it completely ionizes into H+ and Cl- ions.

Ammonia is the conjugate acid of NH2-ion which is a  strong base and becomes more stable by accepting a proton. Therefore, Cl- is an ionic species and also a conjugate base of a very strong acid.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.