Nursing Elites

1. Which compound is a Hydrogen or proton donor, corrosive to metals, causes blue litmus paper to become red, and becomes less acidic when mixed with a base?

• A. Base
• B. Acid
• C. Salt
• D. Hydroxide

Correct answer: B

Rationale: The correct answer is 'Acid.' An acid is a compound that donates protons (H+), is corrosive to metals, and turns blue litmus paper red. When an acid is mixed with a base, they react to form salts and water, resulting in a decrease in acidity. Choices A, C, and D are incorrect because bases accept protons rather than donate them, salts are the products of acid-base reactions, and hydroxides are typically bases, not acids.

2. Which substance forms hydroxide ions when placed in water?

• A. Lemon juice
• B. Battery acid
• C. Vinegar
• D. Lye

Correct answer: D

Rationale: The correct answer is D, lye. Lye, also known as sodium hydroxide (NaOH), is a strong base that forms hydroxide ions (OH-) when placed in water. When lye dissolves in water, it dissociates into sodium ions (Na+) and hydroxide ions, making it an alkaline substance. Lemon juice, battery acid, and vinegar do not form hydroxide ions when placed in water. Lemon juice contains citric acid, battery acid contains sulfuric acid, and vinegar contains acetic acid, none of which produce hydroxide ions when dissolved in water.

3. What is the typical oxidation state of oxygen in most compounds?

• A. -1
• B. -2
• C. 0
• D. -3

Correct answer: B

Rationale: The correct answer is B: "-2". Oxygen usually exhibits an oxidation state of -2 in most compounds. This is due to oxygen's high electronegativity, which causes it to attract electrons, leading to the gain of two electrons in chemical reactions. Choice A (-1) is incorrect because oxygen rarely has an oxidation state of -1 in compounds. Choice C (0) is incorrect as oxygen does not usually have an oxidation state of zero in compounds. Choice D (-3) is incorrect as oxygen does not commonly have an oxidation state of -3 in compounds.

4. Carbon-12 and carbon-14 are isotopes. What do they have in common?

• A. Number of nuclear particles
• B. Number of protons
• C. Number of neutrons
• D. Mass number

Correct answer: C

Rationale: Isotopes are atoms of the same element with the same number of protons (which determines the element) but different numbers of neutrons. Both carbon-12 and carbon-14 have 6 protons (hence they are both carbon atoms) but different numbers of neutrons: carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons. Therefore, the correct answer is the number of neutrons. Choices A, B, and D are incorrect because isotopes may have different numbers of nuclear particles (protons + neutrons), protons, and mass numbers, respectively.

5. What color does phenolphthalein turn in the presence of an acid?

• A. Clear
• B. Blue
• C. Pink
• D. Red

Correct answer: C

Rationale: In the presence of an acid, phenolphthalein turns pink. Phenolphthalein is a pH indicator that is colorless in acidic solutions but turns pink in basic solutions. Therefore, when added to an acidic solution, phenolphthalein will exhibit a pink coloration. Choice A, 'Clear,' is incorrect because phenolphthalein does not remain colorless in the presence of an acid. Choice B, 'Blue,' is incorrect as phenolphthalein does not turn blue in the presence of an acid. Choice D, 'Red,' is incorrect as phenolphthalein does not exhibit a red color in acidic solutions.

Similar Questions