Answer:
13.59
Explanation:
Step 1:
We'll begin by writing out the data from the question.
Mass of NaOH = 55.90g
Volume = 3.6 L
pH =?
Step 2:
Determination of the number of mole NaOH.
Mass of NaOH = 55.90g
Molar Mass of NaOH = 23 + 16 +1 = 40g/mol
Number of mole = Mass/Molar Mass
Number of mole of NaOH = 55.90/40
Number of mole of NaOH = 1.3975 mole
Step 3:
Determination of the molarity of NaOH.
Molarity = mole /Volume
Mole of NaOH = 1.3975 mole
Volume = 3.6 L
Molarity of NaOH = 1.3975/3.6
Molarity of NaOH = 0.388 M
Step 4:
Determination of the concentration of OH- in 0.388 M NaOH
In solution, NaOH will dissociate as follow:
NaOH —> Na+ + OH-
From the equation above,
1 mole of NaOH produced 1 mole of OH-
Therefore, 0.388 M of NaOH will also produce 0.388 M of OH-
The concentration of OH- is 0.388 M
Step 5:
Determination of the pOH of the solution.
pOH = - Log [OH-]
Concentration of OH-, [OH-] = 0.388 M
pOH = - Log [OH-]
pOH = - Log 0.388
pOH = 0.411
Step 6:
Determination of the pH of the solution.
pH + pOH = 14
pOH = 0.411
pH + 0.411 = 14
pH = 14 - 0.411
pH = 13.589
