Q. What is the correct relationship between the pHs of isomolar solutions of sodium oxide (pH₁), sodium sulphide (pH₂), sodium selenide (pH₃) and sodium telluride (pH₄) ?
A) pH₁ > pH₂ ≈ pH₃ > pH₄
B) pH₁ < pH₂ < pH₃ < pH₄
C) pH₁ < pH₂ < pH₃ ≈ pH₄
D) pH₁ > pH₂ > pH₃ > pH₄
Explanation
[Solution from source] These salts are basic by anion hydrolysis. Acid strength rises H₂O < H₂S < H₂Se < H₂Te, so the conjugate bases weaken O²⁻ > S²⁻ > Se²⁻ > Te²⁻ and pH₁ > pH₂ > pH₃ > pH₄. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.