The presence of H+ ions makes a solution acidic and OH- ions makes it alkaline. In the case of Na+ ions, we see that being a positively charged particle, the sodium ion would tend to make the solution more alkaline. The presence of OH- ions generated by the sodium ion would also generate some H+ ions. According to the bronsted lowry definition of an acid, the sodium ion is not an acid. This is because the bronsted lowry definition of an acid states that an acid is a proton donor. The large sodium ion, Na+, is neither an acid nor a base in water.