Which Is the Best Choice for Preparing a Buffer with a PH

question 37

Multiple Choice

Which is the best choice for preparing a buffer with a pH of 3.5?

• A) C₅H₅O₅COOH, K_a = 4.0 × 10^-6
• B) HOC₆H₄OCOOH, K_a = 1.0 × 10^-3
• C) HBrO, K_a = 2.3 × 10^-9
• D) C₆H₄(COOH)₂, K_a = 2.9 × 10^-4
• E) CH₃COOH, K_a = 1.8 ×10^-5

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Definitions:

Labor Rate Variance

The variance between the real labor costs and the projected or normative labor costs.

Variable Overhead Efficiency Variance

The difference between the actual variable overhead incurred and the expected (or standard) variable overhead based on output levels.

Direct Materials Purchases Variance

The difference between the actual cost of direct materials purchased and the expected cost, based on standard prices and quantities.

Standard Costs

Predetermined or estimated costs used for budgeting and measuring performance, typically under ideal operating conditions.