If a buffer system containing hydrofluoric acid and fluoride (pKa = 3.17) initially has a pH of 3.22 and base is added until a new pH of 4.69 is obtained, how has the ratio of fluoride to hydrofluoric acid changed?

A.
from 1.12 : 1 to 33.1 : 1
B.
from 1 : 1.12 to 33.1 : 1
C.
from 1 : 1.12 to 1 : 33.1
D.
from 1.12 : 1 to 1 : 33.1

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .

Answerhave membrane-bound organelles;

Ithink about 50 % of an original isotope's number of atoms remain