Arrange these acids from weakest to strongest: HClO2, HCN, HF, HCl

Question

Ik the order is :
HCN < HF < HClO2 < HCl

but how exactly does one come to that conclusion with no necessary given information (Ka values?). Is there a way to memorize? or a trick? to know what acid is stronger than the other by the chemical formula.

Thanks!

Answer 1

http://clas.sa.ucsb.edu/staff/Resource%20folder/Chem109ABC/Acid,%20Base%20Strength/Table%20of%20Acids%20w%20Kas%20and%20pKas.pdf

You have them right, so you do have to look at Ka.

Answer 2

so without Ka one wouldn't be able to find out the order?

Answer 3

Not exactly, all you can do without Ka is approximate, depending on the structure of the cation. It is only very rough.