scavenger and 300 g of 0 10n hcl electrolyte was used in each case the electrolysis was carried out as described above table 2______________________________________weight of volume ofnitromethane g hydrogen gas ml ______________________________________0 0 2 10 15 1 40 30 1 10 45 0 90 75 0 41 05 0 31 50 0 13 0 0 012 0 0 030 0 0 0______________________________________ these results show the hydrogen scavenger can reduce the amount of hydrogen evolution even at concentrations as low as about 0 05 the effectiveness increases as the concentration of the hydrogen scavenger increases until essentially no hydrogen is evolved concentrations as high as about 10 can be used other metals were used as the cathode materials to show the influence of the cathode material on hydrogen evolution the hydrogen evolution was determined for each cathode material in 0 10n hcl in the absence of a hydrogen scavenger and in then in the presence of the hydrogen scavenger the hydrogen scavenger in this evaluation was 0 5 by weight of 2 nitroethanol the evaluation was carried out twice and the results averaged table 3______________________________________ hydrogen evolution without withcathode hydrogen hydrogenmaterial scavenger scavenger______________________________________copper 2 1 0 4aluminum 2 2 0 2graphite 2 2 0 2nickel 2 2 0 4stainless steel 2 2 0 4zinc 2 2 0 2tin 2 2 0 3iron 2 2 0.