When sodium reacts with water hydrogen gas and sodium hydroxide are produced

Reaction of Sodium and Water

Purpose To observe the reactivity of a metal

with water

Demonstration Only a tiny piece of sodium was used

since the reaction is exothermic and also produces hydrogen gas, too much heat would cause the hydrogen to explode

• 2H2 + O2 2H2O

As the metal reacted, it hissed on a cushion of hydrogen gas

The sodium hydroxide produced caused the indicator to turn pink

Concepts1. Metals

2. Bases

3. Reactions of Metals

1. Metals Most of the elements of the Periodic

Table are metals Metals have common properties

shiny maleable ductile electrically conductive

Some metals are more reactive than others

Group IA metals are the most reactive

2. Bases A base is a substance that

produces hydroxide ion when dissolved in water

Common bases are hydroxides of Group IA and Group IIA metals

LiOH lithium hydroxide

NaOH sodium hydroxide

KOH potassium hydroxide

Mg(OH)2 magnesium hydroxide

Ca(OH)2 calcium hydroxide

3. Reactions of Metals Metals commonly react with acids

Metals of Group IA react with the very weak acid, water

Metal + H2O Metal hydroxide + H2

Reaction of a Group IA metal with water gives a metal hydroxide and hydrogen gas

Conclusions Sodium was more reactive than

other Group II metals Sodium was so reactive that it

reacted with water Group IA metals such as sodium

are the most reactive metals When Group IA metals reacted with

water hydrogen gas was produced in addition to a metal hydroxide

Comments This demonstration is an example of a

redox reaction which is a double replacement reaction

Na + H-OH NaOH + H2

sodium metal has oxidation number of zero but ends up as 1+

hydrogen in water has oxidation number of 1+ but ends up as zero in hydrogen gas

Magnesium is a Group IIA metal that will not react with water but will react with acids