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: 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 #2: 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 #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.

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Why is ethanoic acid a weak acid?

More Questions on TEAS 7 Science

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

Answer Explanation

Q #2: What ions make ammonia solution alkaline?

Answer Explanation

Q #3: Strong bases are:

Answer Explanation

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