Is #HNO_2# considered a strong or weak acid?

1 Answer
May 12, 2017

Generally, we consider strong acids to dissociate more in water than hydronium ions do. Since the #"pKa"# of hydronium is about #-1.7#, we consider strong acids to have #"pKa"#s below #-1.7#. That is, they should have #K_a# values around #100# or above.

#"HNO"_2# has a #K_a# of #4.0 xx 10^(-4)#, which is quite a bit less than #100#, so we consider it a weak acid.