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8 multiple-choice questions and 13 flashcards on Acids, Bases, and pH, about 5% of the High School Chemistry bank. Every one carries a written rationale.
Acids, Bases, and pH is one of 12 chapters in CoStudy's High School Chemistry bank, and it holds 8 of the bank's 150 multiple-choice questions — roughly 5% of the total. That proportion is not arbitrary: chapters follow the certifying body's published exam outline, and the number of questions in each is set by that domain's published weight, so the share of your practice time this chapter takes matches the share of the real exam it accounts for.
Studying by chapter is worth doing once you have a diagnostic score. A single overall percentage tells you whether you are close; it does not tell you which domain is dragging. Working a weak chapter in isolation, and re-testing it in isolation, is the fastest way to move a score that has stalled — and it is why the mock exams in CoStudy report by domain rather than as one number.
1 questions drawn from this chapter, with the full rationale shown — the controlling principle behind the right answer, and why each wrong option tempts and fails.
Which is the pH of a strong acid solution?
Answer: E — < 7 (pH 0-6, acidic; lower pH = more acidic)
pH scale 0-14. Acidic: 0-6.99 (e.g., HCl ~0). Neutral: 7 (pure water). Basic: 7.01-14 (e.g., NaOH ~14). pH = -log[H⁺]. Each unit = 10× change in H⁺ concentration. NGSS HS-PS1-4.
4 cards from the 13 in this chapter.
What is 'pH'?
A scale (0-14) measuring how acidic or basic a solution is.
What's an 'acid' (Arrhenius definition)?
A substance that produces H⁺ ions in water. Like HCl.
What pH is neutral?
7.
Worked example: Find pH when [H⁺] = 2.5 × 10⁻⁴ M.
Step 1 — Formula: pH = −log[H⁺]. Step 2 — Plug in: pH = −log(2.5 × 10⁻⁴). Step 3 — Split: −(log 2.5 + log 10⁻⁴) = −(0.40 + (−4)) = −(−3.60). Step 4 — pH = 3.60.
These are a sample. The full Acids, Bases, and pH chapter runs 21 items with per-chapter progress tracking, on the web and in the iOS app.
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