Sodium in water, formation of NaOH visualized - 2Na + 2H2O → 2Na+ + 2OH-- + H2 + heat

simple, but nice experiment is adding sodium metal to water. The piece of sodium metal melts and skirts over the surface of the water, while producing hydrogen gas, and sodium hydroxide is going in solution.

The formation of sodium hydroxide can nicely be visualized when a few drops of solution of phenolphtalein is added to the water.

The result of this experiment easily can be explained. The sodium reacts with water: 2Na + 2H2O → 2Na+ + 2OH-- + H2 + heat

The hydroxide ions make the solution strongly alkaline. The phenolphtalein indicator turns pink/red at high pH. The higher density of the solution of NaOH causes the solution to sink to the bottom, giving rise to the nice patterns.

source : woelen.homescience.net

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Science & Technology

Tags:

• Sodium in water
• formation of NaOH visualized