C
The elements are Lithium and Beryllium— just look at the mass number on the periodic table
The first one has 35 atoms and the elements hydrogen, oxygen and chlorine
The second one has 9 atoms and the elements sodium, carbon, and helium
One of the best buffer choice for pH = 8.0 is Tris with Ka value of 6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value:
pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is
pKa = -log Ka
= -log (6.3x10^-9)
= 8.2
We know that buffers work best when pH is equal to pKa:
pKa = 8.2 = pH
Therefore Tris would be a best buffer at pH = 8.0.
I say the answer is The ratio of oxygen atoms to hydrogen atoms in a molecule of sugar is 2 to 1
