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How sodium reacts with water

Answer Text:
How Sodium reacts with water.
Procedure:
- A small piece of sodium metal is cut and dropped into a trough containing water;
- The resultant solution is tested with litmus paper;
Diagram of apparatus:

Observations and explanations:
- The metal floats on the water surface; because it is less dense than water;
- A hissing sound is produced; due to production of hydrogen gas;
- It vigorously melts into a silvery ball then disappears because reaction between water and sodium is exothermic (produces heat).
The resultant heat melts the sodium due to its low melting point.
- It darts on the surface; due to propulsion by hydrogen;
- The metal may burst into a golden yellow flame; because hydrogen may explode into a flame which then burns the sodium;
- The resultant solution turns blue; because sodium hydroxide solution formed is a strong base;
(b). Reaction equations.
Equation I
`2Na(s) + 2H_2O(l) → 2NaOH(aq) + H_2(g)`;
Equation II
`4Na(s) + O_2 (g) → 2Na_2O(s)`;
Equation III:
`Na_2O(s) + H_2O(l) → 2NaOH(aq)`
Effect of resultant solution on litmus paper; - Litmus paper turns blue; sodium hydroxide formed is highly soluble in water; releasing a large number of
hydroxyl ions which result into alkaline conditions // high pH;