In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. Balanced chemical equation for this reaction is given below.
Na-sodium , H2o- water, H-hydrogen gas and NaOH- aqueous sodium hydroxide.
Two atoms of Na react with two atoms of water and this reaction will give us H (hydrogen gas) and two atoms of NaOH (aqueous sodium hydroxide).
2Na + 2 H2o = H2 +2NaOH.