The pH of a fruit juice is 3.9. Find the hydronium ion concentration [H3O^+], of the juice Use the formula pH= -log[H3o^+] The hydronium ion concentration [H3o^+] is approximately moles per liter. (Use scientific notation. Use the multiplication symbol in the math palette as needed. Round to the nearest tenth as needed. ) Solution -3.9 = log[h30+]Multiply both sides by -1 10^(-3.9) = [H3O+] Rewrite this in exponential form. 1.2 X 10^(-4)M The hydrogen ion concentration. The hydronium ion [H3O+]concentration is approcimately 1.2 X10^(-4) moles/litre.