In doing so, hydrolysis reaction slows down in a much lesser extent as compared to pure water (see Figure (a)) and virtually completes at the final pH values of 4.3-4.5 for the acetic and citric acids, and about 2 for the oxalic acid. For the citric and acetic acids, the pH after hydrolysis changes insignificantly with the increase of acid concentration testifying about buffer nature of the solutions "citric acid / magnesium citrate" and "acetic acid / magnesium acetate". This is not the case when using oxalic acid, due to low solubility of magnesium oxalate in water (see Table ) thus requiring more acidic medium (pH~2) to achieve completion of the hydrolysis. Nevertheless, at the concentrations of oxalic acid ≥3 wt.% / 0.33M, the hydrogen yield approaches 100% (Figure ).