Q18 of 28 Page 187

The hydrogen ion concentration of a solution is 1 X 10 -8 M

i) What is the PH of the solution?


ii) What is the POH of the solution?


iii) Is the given solution, acidic or basic?.

(i) We are given that the hydrogen ion concentration of a solution is = [H+] = 1 X 10-8 M

We know that : -


pH = - log10 [H+]


⇒ pH = - log10 [1 X 10-8 ]


⇒ pH = -[ log101 + log1010-8 ]


Now, log101 = 0


⇒ pH = -[0 + (-8) log1010 ]


Now, log1010 = 1


⇒ pH = -[0-8 ]


⇒ pH = -[-8]


⇒ pH = 8


Hence, the pH of the solution is 8.


(ii) According to relation we have : -


PH + pOH = 14


⇒ 8 + pOH = 14


⇒ pOH = 14 – 8


⇒ pOH = 6


Hence, the pOH of the solution is 6.


(iii) As the pH of the solution is 8 which is greater than 7. Hence, the given solution is basic.


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