The correct answer is option E.
Explanation:
The pH of the solution is defined as negative logarithm of hydrogen ions concentration in a solution. Mathematically written as:
[tex]pH=-\log[H^+][/tex]
The pOH of the solution is defined as negative logarithm of hydroxide ions concentration in a solution. Mathematically written as:
[tex]pOH=-\log[OH^-][/tex]
The sum of ph and pOH is equal to 14.
pH + pOH = 14
A solution has a pH of 4.20.
[tex]pOH=14-pH=14-4.20=9.8[/tex]
[tex]pOH=9.8=-\log[OH^-][/tex]
[tex][OH^-]=1.58\times 10^{-10} M\approx 6.0\times 10^{-10} M[/tex]
Hence, the correct answer is option E.
