The Ka is 0.0104.
To solve for the Ka, the formula is Ka = [H+][ClO-]/[HClO].
In order to determine the value of H+, the formula is H+ = 10^-pH (the pH here
is 1.80). This yields 0.015848931924611134. In the ICE table, since H+ is the same
value as ClO, then the ClO is also 0.015848931924611134. The HClO is the 0.04 -
0.015848931924611134. Substituting the values to the earlier mentioned
equation, the answer is 0.01040072606175673227903507631149 or simply, 0.0104.
