Final answer:
The 10.0g ionic solid in a hand-warmer that interacts with water is likely sodium acetate, which when triggered, crystallizes exothermically to produce heat. This process is not specifically a neutralization reaction but a precipitation reaction that stems from a supersaturated solution.
Step-by-step explanation:
The task is to choose an ionic solid for a hand-warmer with 10.0g of the solid and an inner pouch containing 40.0ml of water to utilize an exothermic process. The reaction types listed include combustion, neutralization, redox, and displacement reactions. However, the most suitable type of reaction for a hand warmer which involves an ionic solid and water is a dissolution followed by a precipitation reaction. This is illustrated by a hand warmer that contains a supersaturated solution of NaC₂H3O₂ (sodium acetate). When the metal disc inside the hand warmer is flexed, it triggers the rapid crystallization of the sodium acetate, which is an exothermic process that releases heat.
The conversion from NaC₂H3O₂ (aq) to NaC₂H3O₂ (s) is the process that produces heat. This reaction is suitable because it is not only exothermic but also reusable; reheating redissolves the sodium acetate, allowing for repeated use of the hand warmer. Therefore, the correct answer to the student's question would be 'b) Neutralization reaction', if we consider the ionic solid to be sodium acetate, which does not undergo a neutralization reaction but rather a dissolution and precipitation process that releases heat.