Neco Model Questions Vol1 2020 Chemistry Question 1

Practice objective / multiple choice question 1 from the 2020 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2020 Chemistry Objective / Multiple Choice Medium Difficulty
Question 1 NECO_MODEL_QUESTIONS_VOL1 • 2020 • CHEMISTRY • objective

A buffer solution is prepared by mixing a weak acid HA (Ka = 1.0 × 10⁻⁵) with its sodium salt NaA. The total concentration of acid plus conjugate base in the final solution is 0.200 M and the measured pH is 4.75. Initially the solution contained only HA at 0.200 M before any NaA was added. Determine (a) the ratio \([A^-]/[HA]\) in the buffer and (b) the concentration of NaA that must be added (in M) to obtain the required pH.

Answer Options

A. 0.600; 0.0720
B. 0.562; 0.0800
Correct Answer C. 0.562; 0.0720
D. 0.500; 0.0600
Correct Answer
C
Correct Option:
0.562; 0.0720

About This Question

This is Neco Model Questions Vol1 2020 Chemistry Question 1. It is one of the objective questions from the 2020 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Medium .

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