Question

pH of aqueous solution of potassium hydroxide at 298 K temperature is 11.65. The initial volume of this solution is made 6 times by addition of water. What will be the pH of the diluted solution ?

Page 152 Chapter - 7.Acids, Bases and Salts

Answer 1

Answer:

pH of aqueous solution of potassium hydroxide at 298 K temperature is 11.65. The initial volume of this solution is made 6 times by addition of water. What will be the pH of the diluted solution ?

Answer 2

Dear student,

◆ Answer -

pH' = 10.87

● Explaination -

pOH of KOH solution is given by formula -

pOH = 14 - pH

pOH = 14 - 11.65

pOH = 2.35

Now, formula for [OH-] is -

pOH = -log[OH-]

2.35 = -log[OH-]

[OH-] = antilog(-2.35)

[OH-] = 4.467×10^-3

When this solution is dilated by 6 times, hydroxyl ion concentration will reduce 6 times.

[OH-]' = [OH-]/6

[OH-]' = 4.467×10^-3 / 6

[OH-]' = 7.445×10^-4

Now pOH' will be -

pOH' = -log[OH-]

pOH' = -log(7.445×10^-4)

pOH' = 3.129

Now, new pH will be -

pH' = 14 - pOH'

pH' = 14 - 3.129

pH' = 10.87

Therefore, pH of the diluted solution will be 10.87.

Thanks dear...