If I have storage tank containing 3.8 X 10E5 liters of water that is contaminated with NaOH and has a pH of 10.82. What volume of 0.1 M HCl is required to bring the pH= 7.0?

Answer 1

I should call your attention to the misuse of symbols. I assume you meant 3.8E5 or you could have written 3.89 x 10^5.
How many mols NaOH do you have.
pH = 10.82; therefore, pOH = 14.0-10.82 = 3.18 and (3.18 = log(OH^-); therefore,(OH^-) = 6.6E-4.
Then mL x M NaOH = mL x M HCl. Solve for mL HCl.