Equilibrium - Result Question 46
####48. Calculate the $pOH$ of a solution at $25^{\circ} C$ that contains $1 \times 10^{-10} M$ of hydronium ions, i.e. $H_3 O^{+}$.
[2007]
(a) 4.000
(b) 9.0000
(c) 1.000
(d) 7.000
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Solution:
- (a) Given $[H_3 O^{+}]=1 \times 10^{-10} M$ at $25^{\circ} C[H_3 O^{+}][OH^{-}]=10^{-14}$
$\therefore[OH^{-}]=\frac{10^{-14}}{10^{-10}}=10^{-4}$
Now, $[OH^{-}]=10^{-pOH}=10^{-4}$
$\therefore pOH=4$
