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Chemistry · FRQ Trainer

Free-response 1 of 59 · Acids & Bases

10 pts our rubric

The real Chemistry Section II is 7 free-response questions in 105 minutes, 50% of your score. 3 long questions worth 10 points each and 4 short questions worth 4 points each — 46 raw points. This prompt is ours, written to the same skills — score it against the rubric below, not against that structure.

Prompt

A 0.500 L buffer solution contains 0.20 M acetic acid (CH₃COOH, Ka = 1.8 × 10⁻⁵) and 0.20 M sodium acetate (CH₃COONa).

aCalculate the pH of the buffer.3 pts

bCalculate the pH after 0.010 mol of solid NaOH is added. Assume no change in volume.4 pts

cExplain why this solution resists changes in pH.2 pts

dIdentify which component of the buffer reacts with added HCl.1 pt

Keep writing to unlock scoring (0/120)

Write your response first — then grade it with AI or self-score against the rubric.