The given question is lacking some details, the complete question is following
Question:
An aqueous solution at 25 °C has a OH⁻ concentration of 2.5 x 10⁻⁴ M . Calculate the H₃O⁺ concentration. Be sure your answer has the correct number of significant digits
Answer:
Concentration of H₃O⁺ is:
[tex][H_{3}O^{+}]=4.0X10^{-9} M[/tex]
Explanation:
In aqueous solutions the product of the concentration of hydronium ions H₃O⁺ and hydroxide ions OH⁻ is 1.0 x 10⁻¹⁴. This value is the dissociation or ionization constant of water at 25 °C. Its formula is given as:
[tex]Kw = [H_{3} O^{+}][OH^{-} ][/tex]
[tex]1.0 X 10^{-14}= [H_{3}O^{+}](2.5 X 10^{-4})[/tex]
[tex][H_{3}O^{+}]= \frac{1.0X10^{-14}}{2.5 X 10^{-4}}[/tex]
[tex][H_{3}O^{+}]=4.0X10^{-9} M[/tex]
P.S: As the smallest number of significant figure in the ratio was two, so the answer contains two significant figures.