Which compound has a value of Ka that is close to 10^-5?
A)NaCl
B)HN03
C)CH3CH2C02H
D)KOH
E)NH3
See the table here.
http://www.mpcfaculty.net/mark_bishop/weak_acid_equilibrium.htm
To determine which compound has a value of Ka close to 10^-5, we need to understand what Ka is. Ka, also known as the acid dissociation constant, is a measure of the strength of an acid in aqueous solution. It represents the equilibrium constant for the dissociation reaction of an acid.
The larger the value of Ka, the stronger the acid. Conversely, the smaller the value of Ka, the weaker the acid. Therefore, to find the compound with a value of Ka close to 10^-5, we need to look for a weak acid.
Let's analyze each compound to determine their acidic properties:
A) NaCl - This compound is a salt and does not act as an acid. It does not dissociate into ions in water, so it does not have a Ka value.
B) HN03 - This compound is nitric acid, a strong acid. It readily dissociates into H+ and NO3- ions in water. It has a large Ka and is not close to 10^-5.
C) CH3CH2C02H - This compound is acetic acid, a weak acid. It partially dissociates into CH3CH2COO- and H+ ions in water. Acetic acid has a Ka value of approximately 10^-5, which is close to the desired value.
D) KOH - This compound is potassium hydroxide, a strong base. It does not dissociate into H+ ions in water, so it does not have a Ka value.
E) NH3 - This compound is ammonia. Although it can act as a weak base, it is not an acid. It does not have a Ka value.
Therefore, the compound with a value of Ka close to 10^-5 is option C) CH3CH2C02H, which is acetic acid.