Activity 3.9 NCERT Class 10 Science, Chapter 3 Metals and Non-metals
Activity 3.9 asks us to burn various metals and observe their flame.
Not all metals burn easily, Copper and aluminium take time to burn.
Aluminium: Silver white
Copper :blue flame
Highly reactive metals like sodium and potassium reacts with water and form soluble hydroxide. But most other metals are not so reactive. So they are not soluble in water.
Only some metal oxides that from metal hydroxide with water, are soluble in water. Else they are insoluble. Beryllium and magnesium are exceptions as they are slightly soluble in water.
Metal oxide + H2O(l) ———> Metal Hydroxide.
Metals are highly reactive elements. They react with oxygen readily to form metal oxides. Highly reactive metals like lithium, sodium, potassium, beryllium, magnesium react spontaneously. Other metals like Aluminum, copper take time to burn. It produces a specific flame colour. Many times flame colour is used to find the constituent of the substance.
Metal + O2(g) ———> Metal oxide(s)
Metals on the heating burn to produce its oxides. During this process, they produce characteristic flames.