A. is more basic.
B. has no OH- ions
C. has more H+ ions.
D. has a higher pH.
E. all of the choices are correct.What is pH?
pH=7 or -log[H+]=7 or log[H+]=-7, take antilog of both sides, [H+]=10^-7
So a pH 7 has 10^-7 H+ ions, while a pH 9 has 10^-9 H+ ions. remember that -9 is smaller than -7, so ph9 has fewer H+ ions than pH 7.
So the pH 7 has more H+ions, it is more acidic (acids are less than ph7, bases are greater than pH7)
you know D (and therefore E) are wrong because pH 7 is lower pH than pH 9.
we can't say whether B is corrrect or not, because we don't know for sure if it's an aqeous solution, which OH- as counterions to the H+ (but it likely is aquous and both have OH- ions)
It is not more basic, because the lower the pH, the higher the concentrasion of H+ ions, and the more acidic.