The tests of the apparatus described above were carried out using powders of magnesium (m=80-150 g) or magnesium hydride (m=40 g) and 1.6 l of 4M solution of citric acid in the reservoir (3), so as the maximum molar ratio "Acid/Mg" or "Acid/MgH2" varied between 1.05 and 3.8. In all cases the maximum amount of the generated H2 was 0.79 Nl/g for Mg (85.7% yield of Reaction 1) and 1.42 Nl/g for MgH2 (83.3% yield of Reaction 2).