A solution with [ ] of 5 × has a pH of ________.
A)2.3
B)-2.3
C)11.7
D)7.0
E)5.0

Question

A solution with [  ] of 5 ×  has a pH of ________.
A)2.3 
B)-2.3 
C)11.7 
D)7.0 
E)5.0

Quizplus · Accepted Answer

The presence of the term "pH" suggests that this is a question about acid-base chemistry. The notation "11eaa640_f81a_b8e6_842f_27b4677f3787_TB6909_11" represents a chemical compound, likely an acid or a base. Without knowing the exact compound, it is difficult to determine the pH of the solution. However, we can make some educated guesses.

The fact that the solution is a "solution with [11eaa640_f81a_b8e6_842f_27b4677f3787_TB6909_11] of 5 × 11eaa640_f81a_dff7_842f_6f01c192b27a_TB6909_11" suggests that we are dealing with a weak acid or weak base. If we assume that this is a weak acid, we can write the following equation for the dissociation of the acid:

HA + H2O ⇆ A- + H3O+

The equilibrium constant for this reaction is known as the acid dissociation constant, Ka. If we know the value of Ka for the acid, we can calculate the pH of the solution using the following equation:

pH = -log[H3O+]

Unfortunately, we do not know the value of Ka for the acid in question. However, we can make some generalizations. If the acid is weak, its Ka value will be small, and its pH will be higher than the pH of a strong acid solution of the same concentration. If we assume that the acid is weaker than acetic acid (which has a Ka of 1.8 x 10^-5), we can estimate the pH of the solution to be greater than 2.3. This eliminates options A and B.

We can also make some generalizations about the pH of weak bases. If we assume that the compound is a weak base, we can write the following equation for the dissociation of the base:

B + H2O ⇆ BH+ + OH-

The equilibrium constant for this reaction is known as the base dissociation constant, Kb. If we know the value of Kb for the base, we can calculate the pH of the solution using the following equation:

pH = 14 - pOH
pOH = -log[OH-]
Kb = [BH+][OH-]/[B]

Again, we do not know the value of Kb for the base in question, but we can make some generalizations. If the base is weak, its Kb value will be small, and its pH will be lower than the pH of a strong base solution of the same concentration. If we assume that the base is weaker than ammonia (which has a Kb of 1.8 x 10^-5), we can estimate the pH of the solution to be less than 11.7. This eliminates option C.

This leaves option D, 7.0, and option E, 5.0. However, it is very unlikely that the pH of a solution containing a weak acid or a weak base would be exactly 7.0 or 5.0. These values correspond to neutral and acidic solutions, respectively, and do not reflect the properties of weak acids or bases. Therefore, the best answer is C, 11.7, which was eliminated based on our estimates of the strength of the acid or base.

A Solution with [ ] of 5 ×