b REACTION OF SODIUM WITH WATER i A very safe way of demonstrating the reaction of sodium and water is to drop a very small piece of sodium into a swimming pool ii Pour a 2 cm layer of kerosene on to the surface of water in a testtube Drop a 3 mm diameter piece of sodium into the kerosene Be careful Sodium sinks in the kerosene and float in the water Adjust the layer of kerosene to be shallow enough to allow the top of the sodium to protrude above the surface This reaction between sodium and the water is much slower than if the sodium had been dropped directly on to the water You can watch the reaction through a hand lens held at the side but never at the top Sodium metal is lighter than water but heavier than kerosene A small area of the sodium suddenly reacts causing a stream of bubbles to appear The stream of bubbles at one side causes movement The irregular shape of the sodium changes to a sphere The sodium melts because the reaction gives off heat Note any variations in light refraction and reflection below the sodium that indicates something dissolving in the water Slight smoke where the hot sodium is above the kerosene level suggests a slight reaction with air Test the gas bubbles for oxygen or hydrogen