HESI A2 Chemistry Questions

Correct Answer: D

Rationale: The correct answer is D: hydriodic acid. In aqueous solution, HI dissociates into H+ and I- ions, forming hydriodic acid. Choice A (hydroiodic acid) is incorrect as it does not reflect the presence of water in the compound. Choice B (hydrogen monoiodide) is incorrect as it incorrectly implies the presence of only one iodide ion. Choice C (hydrogen iodide) is incorrect as it does not specify the compound in aqueous solution. Therefore, the correct term for aqueous HI is hydriodic acid.

Correct Answer: A

Rationale: Silicon is a metalloid because it exhibits properties of both metals and non-metals. It is a semiconductor, has a shiny appearance, and conducts electricity to some extent. Lead is a metal, helium is a noble gas, and aluminum is a metal. Therefore, the correct answer is A: Silicon.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen acceptors. Bases or alkaline solutions are known as hydrogen acceptors because they can accept a hydrogen ion (H+) to form water. This process is known as neutralization. Choices B and C are incorrect because alkaline solutions are not solutions of low pH or hydrogen donors. Choice D, amphoteric, refers to substances that can act as both acids and bases, which is not the definition of bases or alkaline solutions.

Correct Answer: C

Rationale: The correct answer is C because an acid reacts with bases to form salt and water through a neutralization reaction. This property is known as the acidic property. Choice A (Bitter taste) is incorrect as acids generally taste sour, not bitter. Choice B (Slippery feel) is incorrect as this describes the texture of bases, not acids. Choice D (Sweet taste) is incorrect as acids typically taste sour, not sweet. In summary, the property of reacting with bases is unique to acids, distinguishing them from other substances.

Correct Answer: B

Rationale: The correct answer is B: Neon. Noble gases are a group of elements that are inert and have a full outer electron shell, making them stable and unreactive. Neon belongs to the noble gas group in the periodic table, with a full outer electron shell, making it stable. Oxygen (A) is a reactive nonmetal, hydrogen (C) is a nonmetal but not a noble gas, and argon (D) is also a noble gas but not the correct answer in this case.