The question is incomplete. Complete question is:
<span>Consider the given acid ionization constants. identify the strongest conjugate base.
</span>HNO2(aq) 4.6×10−4
HCHO2(aq) 1.8×10−4
HClO(aq) 2.9×10−8
HCN(aq) 4.9×10−10
.........................................................................................................................
Correct Answer: option
4: HCN(aq) 4.9×10−10
Reason:
According to Lowry and Bronsted theory of acid and base. Stronger the acid, weaker will be the conjugate base.
In present case, ionization constant is highest of HCN i.e. 4.9×

. This signifies that, it is the strongest acid. Hence, conjugate base associated with this acid (i.e.

) is the weakest.
The answer is C, i just took the k-12 test~
Elements in group 1-2, 13-18, the number of valence electrons is related to the group number. For example, in the first group, the alkali metals there is one valence electron, however in group 13, there are 3 valence electrons. Valence electrons are also known as the outershell electrons.