What is the pOH of a solution with [tex]$\left[ OH ^{-}\right]=1.4 \times 10^{-13} ?[/tex]
A. 13.15
B. 12.85
C. -13.15
D. 14.00
Answer (2)
We are given the hydroxide ion concentration [ O H − ] = 1.4 × 1 0 − 13 .
We use the formula pO H = − l o g 10 [ O H − ] .
Substituting the given concentration, we have pO H = − l o g 10 ( 1.4 × 1 0 − 13 ) .
Calculating the value, we find pO H ≈ 12.85 . The final answer is 12.85 .
Explanation
Understanding the Problem We are given the hydroxide ion concentration, [ O H − ] = 1.4 × 1 0 − 13 M, and we need to find the pOH of the solution.
Recalling the Formula The pOH of a solution is defined as the negative logarithm (base 10) of the hydroxide ion concentration. The formula is: pO H = − l o g 10 [ O H − ]
Substituting the Value Now, we substitute the given hydroxide ion concentration into the formula: pO H = − l o g 10 ( 1.4 × 1 0 − 13 )
Calculating the pOH Calculating the pOH value: pO H = − l o g 10 ( 1.4 × 1 0 − 13 ) ≈ 12.85
Examples
Understanding pOH is crucial in various real-life applications, such as monitoring water quality in aquariums or assessing the effectiveness of cleaning agents. For instance, in aquariums, maintaining the correct pOH is vital for the health of aquatic life. Similarly, in household cleaning, knowing the pOH of a cleaning solution helps ensure it's effective without being too corrosive. The pOH scale, like pH, provides a simple way to quantify the acidity or alkalinity of a solution, enabling informed decisions in diverse fields.
The pOH of the solution with [OH^-] = 1.4 × 10^-13 can be calculated using the formula pOH = -log[OH^-]. After calculation, the pOH is approximately 12.85, which corresponds to option B. Therefore, the answer is B. 12.85.
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