Neco Model Questions Vol1 2023 Chemistry Question 22

Practice objective / multiple choice question 22 from the 2023 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2023 Chemistry Objective / Multiple Choice Medium Difficulty
Question 22 NECO_MODEL_QUESTIONS_VOL1 • 2023 • CHEMISTRY • objective

A buffer solution is prepared by dissolving 0.250 mol of acetic acid (\(CH_3COOH\), \(K_a = 1.8\times10^{-5}\)) and 0.150 mol of sodium acetate (\(CH_3COONa\)) in 1.00 L of water. Then 0.050 mol of hydrochloric acid (\(HCl\)) is added. (a) Calculate the pH of the solution before the addition of \(HCl\). (b) Calculate the pH after the addition. (c) How many moles of sodium hydroxide (\(NaOH\)) must be added to restore the original pH?

Answer Options

A. Initial pH = 4.30; pH after HCl = 4.27; NaOH needed = 0.060 mol
Correct Answer B. Initial pH = 4.52; pH after HCl = 4.27; NaOH needed = 0.050 mol
C. Initial pH = 4.52; pH after HCl = 4.40; NaOH needed = 0.055 mol
D. Initial pH = 4.74; pH after HCl = 4.10; NaOH needed = 0.045 mol
Correct Answer
B
Correct Option:
Initial pH = 4.52; pH after HCl = 4.27; NaOH needed = 0.050 mol

About This Question

This is Neco Model Questions Vol1 2023 Chemistry Question 22. It is one of the objective questions from the 2023 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Medium .

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