Question

Which of the following oxides will be least acidic?

• A. $P_4{O}_6$
• B. $P_4{O}_{10}$
• C. $A{s}_4{O}_6$
• D. $A{s}_4{O}_{10}$

Answer 1

Answer: (C)

$A{s}_4{O}_6$

Acidic Character of oxides of elements decreases as we move down the group. This means that oxides of Phosphorus are more acidic than oxides of Arsenic.

For oxides of same element, the oxide with higher oxidation state of element is more acidic.

So, the order of Acidic nature of given oxides is $P_4{O}_{10}>P_4{O}_6>A{s}_4{O}_{10}>A{s}_4{O}_6$

So, the least acidic oxide is $A{s}_4{O}_6$.

Hence, Option "C" is the correct answer.