A Level Chemistry OCR Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Prepare effectively for the A Level Chemistry OCR Exam with our valuable resources, including multiple choice questions and hints. Unlock your potential and ace your exam with comprehensive practice materials designed for your success!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

Which substance is considered a strong acid?

Water
Sodium chloride
Hydrochloric acid
Ammonia

The correct answer is: Hydrochloric acid

Hydrochloric acid is considered a strong acid because it completely dissociates in water to produce hydrogen ions (H⁺) and chloride ions (Cl⁻). This complete ionization means that solutions of hydrochloric acid have a high concentration of H⁺ ions, which is characteristic of strong acids. Strong acids are known for their ability to significantly lower the pH of a solution and can react vigorously with bases or other substances. In contrast, water is a neutral substance that does not exhibit acidic properties; sodium chloride is a neutral salt formed from a strong acid (HCl) and a strong base (NaOH), and it does not contribute H⁺ ions in solution. Ammonia is a weak base that does not dissociate to produce a significant amount of H⁺ ions. Thus, hydrochloric acid stands out as the strong acid among the choices presented.