The relationship between solution pH and hydrogen ion concentration (\( \text{H}^+ \)) is defined by the equation:\[\text{pH} = -\log [\text{H}^+]\]With a given pH of 2.7, the equation can be rearranged to determine \( [\text{H}^+] \):\[[\text{H}^+] = 10^{-\text{pH}} = 10^{-2.7}\]The calculation of \( 10^{-2.7} \) yields:\[10^{-2.7} \approx 2.00 \times 10^{-3} \, \text{M}\]However, accounting for significant figures and performing a more precise calculation:\[10^{-2.7} \approx 1.99 \times 10^{-3} \, \text{M}\]Therefore, the hydrogen ion concentration is approximately \( 1.99 \times 10^{-3} \, \text{M} \).