To find the hydronium ion concentration \( t \) for a solution with a pH of 1.4, we can use the equation given:
\[ p(t) = -\log(t) \]
Rearranging this equation to solve for \( t \) gives:
\[ t = 10^{-p(t)} \]
Now we can substitute \( p(t) = 1.4 \):
\[ t = 10^{-1.4} \]
Calculating \( 10^{-1.4} \):
\[ t \approx 0.0398 \text{ mol/L} \]
Thus, the approximate hydronium ion concentration for a solution with a pH of 1.4 is:
A) 0.0398 mol/L