HNO2 is a much weaker acid then HNO3 (strong acid dissociates completely) H2SeO3 is weaker than H3AsO4 but only slightly as both are triprotic acids H2SO4 is weaker than HClO4 but bother are very strong acids. Solution HNO2 is a much weaker acid then HNO3 (strong acid dissociates completely) H2SeO3 is weaker than H3AsO4 but only slightly as both are triprotic acids H2SO4 is weaker than HClO4 but bother are very strong acids..