Given below are two statements :
Statement I : The pentavalent oxide of group-15 element, E₂O₅, is less acidic than trivalent oxide, E₂O₃, of the same element.
Statement II : The acidic character of trivalent oxide of group 15 elements, E₂O₃, decreases down the group.
In light of the above statements, choose most appropriate answer from the options given below :

Solution

Chemistry ma’am · 4 steps

Higher oxidation state means a more acidic oxide, and going down the group the oxides turn basic.

1. Oxidation state rule. For oxides of the same element, the higher the oxidation state, the more acidic the oxide. In E₂O₅ the element is +5; in E₂O₃ it is only +3.
2. Statement I. The +5 centre has a higher charge on a smaller core, so it pulls electron density from oxygen more strongly. That makes E₂O₅ more acidic than E₂O₃. For example, N₂O₅ is more acidic than N₂O₃. Statement I says the opposite, so it is false.

   Oxide	Nature
   N₂O₃, P₄O₆	acidic
   As₂O₃, Sb₂O₃	amphoteric
   Bi₂O₃	basic

3. Statement II. Going down the group, the element becomes more metallic and its oxides become more basic. So the acidic character of E₂O₃ decreases from N to Bi, and Statement II is true.
4. So. Statement I is false and Statement II is true, which is option (d).

The idea to keep. For oxides, acidity rises with oxidation state across the same element and falls down a group as metallic character grows. Check both directions separately.

Answer from the NTA final answer key. Solution by PrepWiser.