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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: Which acid is needed to make ammonium nitrate?

    A. Sulfuric acid

    B. Hydrochloric acid

    C. Nitric acid

    D. Acetic acid

    Answer Explanation

    A) Sulfuric acid: Sulfuric acid is not used in the production of ammonium nitrate. Although sulfuric acid is a widely used acid in various industries, it is not involved in the synthesis of ammonium nitrate.

    B) Hydrochloric acid: Hydrochloric acid is not used in the production of ammonium nitrate. While it is an important industrial acid, it does not react with ammonia to produce ammonium nitrate.

    C) Nitric acid (Correct Answer): Ammonium nitrate is typically produced by reacting ammonia (NH3) with nitric acid (HNO3). The reaction forms ammonium nitrate (NH4NO3), which is a common fertilizer and explosive compound.

    D) Acetic acid: Acetic acid, commonly known as vinegar, is not used in the production of ammonium nitrate. It is a weak acid and does not react with ammonia to form ammonium nitrate.

  • Q #2: Why is dry hydrogen chloride gas not acidic?

    A. Because it does not react with water

    B. Because it does not contain hydrogen ions (H+)

    C. Because it contains hydrogen ions but not chloride ions (Cl-)

    D. Because hydrogen is bonded to chlorine in dry HCl and not dissociated

    Answer Explanation

    A) Because it does not react with water: While dry hydrogen chloride gas does not react with water, the absence of this reaction does not inherently determine its acidity. Acidity is determined by the presence of hydrogen ions in solution.

    B) Because it does not contain hydrogen ions (H+): Dry hydrogen chloride gas does not contain free hydrogen ions, which are characteristic of acidic solutions. However, the absence of hydrogen ions alone does not explain why dry hydrogen chloride gas is not acidic.

    C) Because it contains hydrogen ions but not chloride ions (Cl-): Dry hydrogen chloride gas does not contain free chloride ions, but the presence of hydrogen ions is crucial for acidity. However, the absence of chloride ions alone does not fully explain why dry hydrogen chloride gas is not acidic.

    D) Because hydrogen is bonded to chlorine in dry HCl and not dissociated (Correct Answer): Dry hydrogen chloride gas does not dissociate into hydrogen ions (H+) and chloride ions (Cl-) because there is no water present to facilitate dissociation. Therefore, it does not exhibit acidic properties in the absence of dissociation.

  • Q #3: Why do farmers use ammonium salts on their fields?

    A. To prevent soil erosion

    B. To increase soil acidity

    C. To help plants grow (as fertilizers)

    D. To reduce soil salinity

    Answer Explanation

    A) To prevent soil erosion: While certain soil management practices may involve measures to prevent erosion, the use of ammonium salts specifically does not directly relate to preventing soil erosion.

    B) To increase soil acidity: Ammonium salts, such as ammonium sulfate, can actually decrease soil pH, making the soil more acidic. However, this is not typically the primary reason farmers use these salts.

    C) To help plants grow (as fertilizers) (Correct Answer): Ammonium salts are commonly used as fertilizers because they provide essential nitrogen to plants in a form that they can readily absorb. Nitrogen is a crucial nutrient for plant growth, and ammonium salts serve as a source of nitrogen for crops.

    D) To reduce soil salinity: Ammonium salts are not typically used to reduce soil salinity. Salinity issues in soil are typically addressed through other methods such as leaching or soil amendments, rather than the addition of ammonium salts.