Sodium reacting with water forms sodium hydroxide, NaOH.

Direct answer

  • The hydroxide formed when sodium reacts with water is sodium hydroxide, with the formula NaOH.
  • The overall reaction is: 2Na+2H2O→2NaOH+H2↑2\text{Na}+2\text{H}_2\text{O}\rightarrow 2\text{NaOH}+\text{H}_2\uparrow 2Na+2H2​O→2NaOH+H2​↑, so aqueous sodium hydroxide and hydrogen gas are produced.

Quick Scoop

  • Sodium is a very reactive alkali metal and reacts vigorously with water, releasing heat.
  • In the process, sodium atoms lose electrons to become Na⁺, which pair with OH⁻ from water to give sodium hydroxide in solution.

Extra exam-style note

  • If this appears as a question like “What hydroxide is formed when sodium reacts with water?”, the expected one-word answer is: sodium hydroxide (NaOH).