. What is the correct relationship between the pH
of isomolar solutions of sodium oxide, Na2O(pH1), sodium sulphide, NaS(pH2), sodium selenide, Na2Se(pH3) and sodium telluride Na2Te(pH4)?
(a) pH1 > pH2 > pH3 > pH4
(b) pH1 > pH2 ≈ pH3 > pH4
(c) pH1 < pH2 < pH3 < pH4
(d) pH1< pH2< pH3 ≈ pH4
Correct Option is: A
On moving down a group, basicity decreases due to increase in the atomic size. As we know that more is the basic character, higher is the pH. Hence the solution with highest basicity will have the highest pH.