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What is an appropriate pH value for hydrochloric acid?

A. pH 2-4

B. pH 1-3

C. pH 0-2

D. pH 3-5

Answer Explanation:

Rationale for each choice:

A) pH 2-4: While hydrochloric acid is indeed highly acidic, a pH range of 2-4 would suggest a slightly less concentrated solution. However, this range might still be appropriate for dilute or partially neutralized hydrochloric acid.

A) pH 1-3 (Correct Answer): Hydrochloric acid typically has a very low pH due to its strong acidic nature. A pH range of 1-3 is commonly observed for concentrated hydrochloric acid solutions.

C) pH 0-2: This range suggests an even stronger acidity, which could be true for very concentrated hydrochloric acid solutions, although they might not commonly occur in typical laboratory or industrial settings.

D) pH 3-5: This pH range would indicate a significantly less acidic solution compared to hydrochloric acid. Such a pH range might be more appropriate for weak acids or diluted hydrochloric acid solutions rather than the concentrated form.

Therefore, the Correct Answer is B.

More Questions on TEAS 7 Science

  • Q #1: What is a precipitate?

    A. A gas formed during a chemical reaction

    B. A liquid formed when two aqueous solutions react

    C. A solid formed when two aqueous solutions react

    D. A solution formed during a chemical reaction

    Answer Explanation

    A) A gas formed during a chemical reaction: While gases can indeed be produced during chemical reactions, a precipitate specifically refers to a solid that forms during a reaction.

    B) A liquid formed when two aqueous solutions react: Precipitates are not liquids. They are solids that are formed when certain ions combine to form an insoluble compound.

    C) A solid formed when two aqueous solutions react (Correct Answer): A precipitate is indeed a solid substance that forms when two aqueous solutions react and certain ions combine to create an insoluble compound.

    D) A solution formed during a chemical reaction: A precipitate is not a solution. It is the solid product that separates out of a solution during a chemical reaction due to its limited solubility.

  • Q #2: What do plants use the nitrogen in fertilizers for?

    A. To provide energy for photosynthesis

    B. To build cellulose in cell walls

    C. To build amino acids and proteins

    D. To regulate water uptake

    Answer Explanation

    A) To provide energy for photosynthesis: While nitrogen is essential for various metabolic processes in plants, it is not directly involved in providing energy for photosynthesis. Instead, plants use sunlight to convert carbon dioxide and water into glucose during photosynthesis.

    B) To build cellulose in cell walls: Nitrogen is not directly involved in the synthesis of cellulose, which is primarily composed of glucose units. Cellulose synthesis mainly relies on carbon and hydrogen, which are obtained from carbon dioxide and water during photosynthesis.

    C) To build amino acids and proteins: Plants use nitrogen from fertilizers to synthesize amino acids and proteins. Nitrogen is a crucial component of amino acids, the building blocks of proteins, which are essential for plant growth, development, and various physiological processes.

    D) To regulate water uptake (Correct Answer): Nitrogen plays a role in regulating various physiological processes in plants, including water uptake. It affects the osmotic potential of plant cells and helps regulate the movement of water and nutrients within the plant.

  • Q #3: Strong bases are:

    A. Strong electrolytes

    B. Weak electrolytes

    C. Nonelectrolytes

    D. Also strong acids

    Answer Explanation

    a. Strong electrolytes (Correct Answer): Strong bases completely dissociate into ions in solution, making them strong electrolytes. They conduct electricity well due to the presence of a high concentration of ions.

    b. Weak electrolytes: Strong bases, unlike weak bases, completely dissociate in solution, resulting in a high concentration of ions. Therefore, they are considered strong electrolytes, not weak electrolytes.

    c. Nonelectrolytes: Nonelectrolytes do not ionize in solution and do not conduct electricity. Strong bases, however, ionize completely in solution, making them strong electrolytes.

    d. Also strong acids: Strong bases and strong acids are two distinct types of compounds. Strong bases ionize completely in solution to produce hydroxide ions, while strong acids ionize completely to produce hydrogen ions (H+). They are not the same.