Question

What is the equation for the reaction of tetraphosphorus decaoxide and water and react together and form phosphoric acid?

Answer 1

Hint :We know that the $ {{P}_{4}}{{H}_{10}} $ is phosphorus pentoxide, or tetraphosphorus decaoxide. Phosphorus oxides are used to obtain oxyacids of phosphorus. Tetraphosphorus decaoxide gas is not dried over dehydrating agents as it will react to form another compound with these agents.

Complete Step By Step Answer:
Tetraphosphorus decaoxide gas acts as a Lewis base, as the lone pair of electrons on the nitrogen atom of this gas, can easily be donated. Also it liberates hydroxide ions in water, and is weakly alkaline in water. Due to this basic nature of tetraphosphorus decaoxide, it is dried, so that it does not act as a base.
The drying of tetraphosphorus decaoxide is a useful method for the commercial use of this gas. This method uses tetraphosphorus decaoxide gas to react with oxides to lower its basic nature. Phosphorus pentoxide $ {{P}_{4}}{{H}_{10}} $ , is not a suitable compound to dry tetraphosphorus decaoxide gas. This is because; phosphorus pentoxide is highly reactive in moisture and forms Meta phosphoric acid. The reaction is:
 $ {{P}_{4}}{{O}_{10(s)}}+6{{H}_{2}}{{O}_{(l)}}\to 4{{H}_{3}}P{{O}_{4(aq)}}. $ Further, this, Meta phosphoric acid, reacts with tetraphosphorus decaoxide gas to form a phosphate compound called Meta ammonium phosphate.

Note :
Remember that tetraphosphorus decaoxide gas is prepared through a well-known process, called Haber’s process, where hydrogen and nitrogen react to form tetraphosphorus decaoxide. In order to dry tetraphosphorus decaoxide gas, oxide of calcium, $ CaO $ , called quicklime or calcium oxide, is used. Tetraphosphorus decaoxide passes through freshly prepared quicklime and rapidly dries it.