An alloy of aluminium and gallium in pellet form added to water can be used to generate <answer>hydrogen</answer>. The process also produces alumina, but the expensive gallium, which prevents the formation of an oxide skin on the pellets, can be re-used. This has important potential implications for a <answer>hydrogen</answer> economy, as <answer>hydrogen</answer> can be produced on-site and does not need to be transported.
When you combine an alloy of alluminum and gallium to water, what do you get?
hydrogen