A0.001 molar solution of weak acid has a ph = 4.0. what is the pka of the acid?
a. 4
b. 5
c. 6
d. 7
e. 8

A 0.001 molar solution of weak acid has a pH = 4.0,The pKa is :

B. 5

Explanation:

pH = It is negative logarithm of hydrogen ion concentration.

pH = -log([H+])

Ka = It is the dissociation constant.

pKa = -log(Ka)

The acid dissociates according to the equation given below:

Here , The concentration of A- and H+ will be same

So,

[H+] = [A-].....(1)

Now ,

pH = 4.0

pH = -log([H+])

4.0 = -log([H+])

- 4.0 = log([H+])        take antilog both side::"use scientific calculator"

From equation (1), [A-] =

[HA] = 0.001 M (given)

Insert the value of HA , H+ and A- in Ka

pKa = -log(Ka)

pKa = 5

i believe the answer is c. "baking" is the gerund, while "baking blueberry muffins" would be the gerund phrase. hope this ! : )

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.