Science — AI-generated practice question

When a concentrated acid is added to water, the large volume of water absorbs the heat generated, keeping the solution safe. However, if water is added to a concentrated acid, the small amount of acid cannot absorb the heat produced and the mixture may splash or boil, causing severe burns. The glass container may also crack due to excessive local heating.

Property involved: The dissolving of an acid in water is a highly exothermic process. Adding acid to water ensures the heat is distributed over a large volume of water, making the process safe.

Source: Chapter 2, Section 2.2.1

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• The examiner expects: (1) what happens when water is added to acid (splashing, burns, breakage), (2) what happens when acid is added to water (safe), and (3) naming the property — exothermic process.
• The phrase "acid must always be added slowly to water with constant stirring" is from the textbook — use it.
• Do not confuse "exothermic" with "endothermic." Mixing acid/base with water releases heat — that's exothermic.
• 3 marks = roughly 3 distinct points: safety reason (1) + consequence of wrong method (1) + property name (1).