What is the hydrogen ion concentration in a
solution having a pOH of 5.74?
Answer in units of M.
I initially did 14-5.74=8.26 to find the pH, then I did 10^(-8.26) to find molarity and I got 5.495, which is wrong... what did I do wrong?
5.495 is correct ... but it is (x 10^-9)
The calculation you performed is correct for finding the pH using the pOH value, but you made a small mistake in calculating the hydrogen ion concentration.
To find the hydrogen ion concentration (H+) from the pH, you need to take the base-10 logarithm (inverse of the logarithm with base 10) of the pH value. In this case, it would be 10^(-pH).
Let's calculate it step-by-step:
1. The given pOH value is 5.74. To find the pH, we need to subtract the pOH from 14:
pH = 14 - 5.74
pH = 8.26
2. Now, take the base-10 logarithm of the pH value:
[H+] = 10^(-pH)
[H+] = 10^(-8.26)
Calculating this on a calculator or by using log properties, we get:
[H+] ≈ 5.01 x 10^(-9) M
So, the correct hydrogen ion concentration in the solution is approximately 5.01 x 10^(-9) M.
To find the hydrogen ion concentration in a solution, you need to first convert the pOH to pH using the relationship pH + pOH = 14. So, in this case, 14 - 5.74 = 8.26, which is the pH, not the pOH as you mentioned in your calculation.
After determining the correct pH value, you can then convert it to the hydrogen ion concentration by taking the antilogarithm (inverse logarithm) of the pH value. Since the pH scale is logarithmic, you need to use the base 10. So, you were right to use 10^(-8.26).
However, the value you calculated, 5.495, exceeds the 2 significant figures, which indicates a rounding error or incorrect calculation.
To obtain the correct answer with 2 significant figures, you should round the result to 5.5. Therefore, the hydrogen ion concentration in the solution with a pOH of 5.74 is 5.5 M.