Answer:
% of mass of electrons in C = 0.0272
Explanation:
Atomic no. of carbon = 6
So, no. of electron = 6
Mass of an electron = 
Mass of 6 electrons = 
Mass of C = 12.0107 u
% of mass of electrons in C = 
% of mass of electrons in C = 
<span>The pH is given by the Henderson - Hasselbalch equation:
pH = pKa + log([A-]/[HA])
pH = -log(</span><span>1.3 x 10^-5) + log(0.50/0.40)
pH = 4.98
The answer to this question is 4.98.
</span>