When lithium reacts with water, it produces hydrogen gas and lithium hydroxide. The reaction is highly exothermic and produces a strong base, lithium hydroxide. Two observations can be made when lithium reacts with water: effervescence and a vigorous fizzing and bubbling. The effervescence is due to the production of hydrogen gas, which bubbles out of the solution. The reaction is not accompanied by combustion or an explosion. The reaction is highly exothermic and produces a strong base, lithium hydroxide. The colorless solution is highly alkaline. The reaction lasts longer than the reaction of sodium and water, which is directly below lithium in the periodic chart.