/

Why is ethanoic acid a weak acid?

A. Because it reacts slowly with bases

B. Because it forms a basic solution when dissolved in water

C. Because it only partially dissociates in solution

D. Because it has a low pH value

Answer Explanation:

Rationale for each choice:

A) Because it reacts slowly with bases: The rate of reaction with bases does not determine whether an acid is weak or strong. Ethanoic acid's reaction rate with bases is not a primary factor in its classification as a weak acid.

B) Because it forms a basic solution when dissolved in water: This statement is incorrect. Ethanoic acid is an acid and forms acidic solutions when dissolved in water.

C) Because it only partially dissociates in solution (Correct Answer): Ethanoic acid is considered a weak acid because it only partially dissociates into hydrogen ions (H+) and acetate ions (CH3COO-) in solution. This partial dissociation results in a lower concentration of hydrogen ions compared to strong acids.

D) Because it has a low pH value: While weak acids generally have higher pH values compared to strong acids, the pH value alone does not determine whether an acid is weak or strong. Ethanoic acid's weak acidity is primarily attributed to its partial dissociation in solution, rather than its pH value.

Therefore, the Correct Answer is C.

Q #1: 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.
Q #2: How would you remove unreacted copper oxide from solution?

A. Filtration

B. Distillation

C. Evaporation

D. Decantation

Answer Explanation

A) Filtration (Correct Answer): Filtration is a commonly used method to separate solid particles, such as unreacted copper oxide, from a liquid solution. The solution containing the dissolved copper sulfate can pass through the filter paper, while the solid copper oxide particles are retained on the filter.

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 particles from a liquid solution.

C) Evaporation: Evaporation involves heating the solution to allow the solvent (water) to vaporize, leaving behind the solute (copper sulfate) as solid crystals. While evaporation can concentrate the solution, it does not effectively remove solid particles like unreacted copper oxide.

D) 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 fine solid particles like unreacted copper oxide from the solution. Filtration would be a more suitable method for this purpose.
Q #3: 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.

Free Access on TEAS 7 Exams and Study Notes

Access to all TEAS 7 Exams
Performance Tracking and Analysis
Well Documented and Explained Questions and Answers
2000+ Questions and Correct Answers: Answers Well Explained
Libary of Detailed StudyNotes
Topical Questions and Answers on Examinable topics

Join Now