Question

Phosphorus is manufactured by heating a mixture of ⋯⋯in an electric furnace.
  (A) bone ash and coke
  (B) bone ash and silica
  (C) bone ash,silica and coke
  (D) bone ash, common salt and coke

Answer 1

Hint: As we know, phosphorus is an element of the nitrogen family with the atomic number 15. It is usually found in three forms such as red , white and black. The manufacture of Phosphorus is an electrothermic process.


Complete Solution :
  - Phosphorus is an element of the nitrogen family with the atomic number 15 and has the symbol P. The element is generally found in three states such as white, red and black forms. The white phosphorus is a waxy, soft, flammable substance which consists of tetrahedral ${{P}_{4}}$ molecule and is highly reactive and spontaneously ignites at about $30{}^\circ C$.
- The black phosphorus is the least reactive in room temperature and can be converted to white phosphorus by heating under pressure.It has little commercial value. Similarly , red phosphorus is stable at room temperature and can be converted into the more reactive form white phosphorous by heat.
- Phosphorus can be manufactured by heating a mixture of bone ash, silica and coke in an electric furnace and the process is an electrothermic process. Bone ash contains calcium phosphate and the reactions corresponding to the formation of phosphorous can be represented as follows:
\[\underset{Bone\text{ }ash}{\mathop{2C{{a}_{3}}{{\left( PO \right)}_{4}}}}\,+\underset{Silica}{\mathop{6Si{{O}_{2}}}}\,\to 6CaSi{{O}_{3}}+{{P}_{4}}{{O}_{10}}\]
\[{{P}_{4}}{{O}_{10}}+\underset{Coke}{\mathop{10C}}\,\to \underset{Phosphorus}{\mathop{{{P}_{4}}}}\,+10CO\]

So, the correct answer is “Option C”.

Note: Keep in mind that, since Phosphorus is highly reactive, in order to avoid the oxidation by oxygen which is present in air, it's usually stored in water. Also, phosphorus is insoluble in water too.