6). Which solution has the lowest pH?
A) 1.3 X10–8 M –OH
B) 1.0 X 10–7 M –OH
C) 5.1 X10–5 M –OH
D) 3.9 X 10–8 M –OH
E) 2.3 X 10–3 M –OH
To determine which solution has the lowest pH, we need to compare the concentration of hydroxide ions (-OH) in each solution. The pH is a measure of the concentration of hydrogen ions (H+) in a solution.
In a neutral solution, the concentration of hydrogen ions is equal to the concentration of hydroxide ions. So, if we know the concentration of hydroxide ions, we can determine the concentration of hydrogen ions.
The relationship between hydrogen ion concentration and hydroxide ion concentration is given by the equation:
pH = -log[H+]
Taking the negative logarithm of both sides of the equation, we get:
[H+] = 10^(-pH)
Now, let's calculate the hydrogen ion concentration for each solution:
A) 1.3 x 10^(-8) M -OH:
[H+] = 10^(-pH) = 10^(-(-8)) = 10^8 = 100,000,000 M
B) 1.0 x 10^(-7) M -OH:
[H+] = 10^(-pH) = 10^(-(-7)) = 10^7 = 10,000,000 M
C) 5.1 x 10^(-5) M -OH:
[H+] = 10^(-pH) = 10^(-(-5.1)) ≈ 6.3 x 10^4 M
D) 3.9 x 10^(-8) M -OH:
[H+] = 10^(-pH) = 10^(-(-8)) = 10^8 = 100,000,000 M
E) 2.3 x 10^(-3) M -OH:
[H+] = 10^(-pH) = 10^(-(-3)) = 10^3 = 1,000 M
From the calculations, we can conclude that solution E) (2.3 x 10^(-3) M -OH) has the lowest pH because it has the highest concentration of hydrogen ions.
(H^+)(OH^-) = Kw = 1E-14
If logic won't do it, then substitute into the equation for OH and solve for H^+.