The ph of lemon juice is approximately 2.40. at this ph, the hydronium ion concentration is closest to which concentration? 4.0 × 10¯3 m 0.38 m 5.6 × 10¯4 m 2.5 × 10¯12 m

pH = -log[H₃O⁺(aq)]

here the pH is given as 2.40.

Hence,
  2.40               = -log[H₃O⁺(aq)]
log[H₃O⁺(aq)]  = -2.40
[H₃O⁺(aq)]       = 3.98 x 10⁻³ M
                        = 4.0 x 10⁻³ M

Hence, the hydronium ion concentration in juice is 4.0 x 10⁻³ M.

Since, the pH is less than 7, the juice is acidic.

Sorry i dont understand the question can you rephase it?