Neco 2023 Chemistry Question 10

Practice objective / multiple choice question 10 from the 2023 Neco Chemistry examination.

Neco 2023 Chemistry Objective / Multiple Choice Hard Difficulty
Question 10 NECO • 2023 • CHEMISTRY • objective

Ethylene glycol (HO‑CH_{2}‑CH_{2}‑OH) has a first dissociation constant \(K_{a1}=1.0\times10^{-14}\) and a second dissociation constant \(K_{a2}=1.0\times10^{-15}\). Intramolecular hydrogen bonding in a 0.10 M solution reduces the effective \(K_{a1}\) by a factor of 5.\n\n(i) Calculate the pH of the 0.10 M ethylene glycol solution, assuming only the first dissociation contributes appreciably to \([H^{+}]\).\n(ii) If the hydrogen‑bonding effect were absent (i.e., using the original \(K_{a1}\)), what would the pH be? State the difference \(\Delta pH\) between the two cases.

Answer Options

Correct Answer A. pH (with H‑bonding) = 7.85; pH (without) = 7.50; \(\Delta pH = 0.35\)
B. pH (with H‑bonding) = 7.80; pH (without) = 7.45; \(\Delta pH = 0.35\)
C. pH (with H‑bonding) = 7.85; pH (without) = 7.40; \(\Delta pH = 0.45\)
D. pH (with H‑bonding) = 7.90; pH (without) = 7.55; \(\Delta pH = 0.35\)
Correct Answer
A
Correct Option:
pH (with H‑bonding) = 7.85; pH (without) = 7.50; \(\Delta pH = 0.35\)

About This Question

This is Neco 2023 Chemistry Question 10. It is one of the objective questions from the 2023 Neco Chemistry examination.

Difficulty level: Hard .

View More Neco 2023 Chemistry Questions More Neco Practice Questions Back to Questions

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support