first, we need to calculate Ka in order to determine the pKa.
The formula for Ka = x^2/ initial concentration
initial concentration= 0.0147 M
we need to find x, and we can use the pH to find it because x is the [H+] concentration.
[H+]= 10^-pH----> [H+]= 10^-2.46= 0.00347
Ka= x^2/ initial---------> (0.00347)^2/ 0.0147= 8.18 x 10^-4
now that we have Ka, we can determine pKa using the following formula--> pKa= -log Ka
pKa= -log (8.18 x 10^-4)= 3.087