Chemistry 12th Edition

(a) $H_2SO_4$ is a stronger acid than $H_2SeO_4$ (b) $H_3PO_4$ is a stronger acid than $H_3AsO_4$
(a) 1. Identify the type of acid: $H_2SO_4$ and $H_2SeO_4$ are both oxoacids, and we are going to compare two oxoacids having different central atoms. 2. Compare the oxidation numbers of their central atoms: Since they both have 2 H and 4 O, their oxidation number is the same. 3. Compare their electronegativity; Sulfur is more electronegative than Selenium. The more electronegative the central atom, the stronger is the oxoacid. Thus: $H_2SO_4$ is stronger than $H_2SeO_4$ (b) 1. Following the same steps, we got: - Phosphorus is more electronegative than Arsenic. Therefore: $H_3PO_4$ is stronger than $H_3AsO_4$