/

A solution with a pH of 5.0 _____.

A. has a hydrogen-ion concentration of 5.0M

B. is neutral

C. has a hydroxide-ion concentration of 1 x 10 –9 M

D. None of the above

Answer Explanation:

a. is basic: Incorrect. Solutions with pH values less than 7 are acidic, not basic. A pH of 5.0 indicates an acidic solution.

b. has a hydrogen-ion concentration of 5.0M: Incorrect. The pH value does not directly provide information about the concentration of hydrogen ions. pH is a logarithmic scale that measures the concentration of hydrogen ions in a solution.

c. is neutral: Incorrect. Solutions with a pH of 7 are considered neutral. A pH of 5.0 indicates an acidic solution.

d. has a hydroxide-ion concentration of 1 x 10 –9 M: Incorrect. This statement relates to the calculation of hydroxide-ion concentration in a neutral solution using the Kw value (the ion product of water). It does not directly pertain to the pH value of the solution.

Therefore, the Correct Answer is D.

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: How can copper sulfate crystals be separated from copper sulfate solution?

    A. Filtration

    B. Distillation

    C. Decantation

    D. Evaporation

    Answer Explanation

    A) Filtration: Filtration is not suitable for separating dissolved substances from a solution. It is typically used to separate solid particles from a liquid mixture.

    B) Distillation: Distillation is a process used to separate components of a mixture based on differences in their boiling points. It is not typically used to separate solid crystals from a solution.

    C) Decantation: Decantation involves pouring off the liquid portion of a mixture, leaving the solid behind. While it can be used to separate solid and liquid phases, it may not effectively separate dissolved copper sulfate from the solution.

    D) Evaporation (Correct Answer): Evaporation involves heating the solution to allow the solvent (water) to vaporize, leaving behind the solute (copper sulfate) as solid crystals. This process is commonly used to obtain solid crystals from a solution.

  • Q #3: What ions make ammonia solution alkaline?

    A. Cl- ions

    B. H+ ions

    C. Na+ ions

    D. OH- ions

    Answer Explanation

    A) Cl- ions: Chloride ions (Cl-) are typically found in salts and do not contribute directly to the alkalinity of ammonia solution.

    B) H+ ions: Hydrogen ions (H+) typically characterize acidic solutions, not alkaline solutions. Ammonia solution doesn't contain H+ ions.

    C) Na+ ions: Sodium ions (Na+) are typically found in salts and do not contribute directly to the alkalinity of ammonia solution.

    D) OH- ions (Correct Answer): Ammonia solution becomes alkaline due to the presence of hydroxide ions (OH-). Ammonia (NH3) reacts with water to form ammonium ions (NH4+) and hydroxide ions (OH-), increasing the concentration of OH- ions and making the solution alkaline.