Oxalic acid,
H 2
​
C 2
​
O 4
​
, is a relatively strong acid despite being an organic acid. The two pKa values for oxalic acid are
1.23
and 4.19. The titration curve between
0.10 moldm −3
H 2
​
C 2
​
O4 m
0.20 moldm −3
NaOH
is given below. State and explain why each of the following statements are correct or wrong. I. The volume of
H 2
​
C 2
​
O 4
​
used in the titration is
20.0 cm 3
​
. II. The initial
pH
of
H 2
​
C 2
​
O 4
​
is
1.1
[Ignore the effects of the second
pKa
]. III. The points
V,X
and
Z
are made up of conjugate acid-base pairs