Answer
(a) $H_2SO_4$ is a stronger acid than $H_2SeO_4$
(b) $H_3PO_4$ is a stronger acid than $H_3AsO_4$
Work Step by Step
(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 $H_3AsO_4$
