how to make phosphoric acid?

Answer 1

The most commonly used method (called the thermal method) is to burn white phosphorus in air, giving Phosphorus pentoxide:

P4 (s) + 5 O2 (g) --> P4O10 (s)

This oxide is then dissolved in dilute phosphoric acid to give pure concentrated phosphoric acid:

P4O10 (s) + 6 H2O (l) --> 4 H3PO4 (aq)

Another method is called the wet method and it uses Sulfuric acid to disolve Calcium phosphate:

3 H2SO4 (aq) + Ca3(PO4)2 (s) --> 2 H3PO4 (aq) + 3 CaSO4 (s)

Answer 2

How To Make Phosphoric Acid

Answer 3

Preparation of phosphoric acid
There are two distinct kinds of phosphoric acid: Thermal phosphoric acid and Wet phosphoric acid.

Thermal phosphoric acid: This very pure phosphoric acid is obtained by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. This is the cleanest way of producing phosphoric acid, since most impurities present in the rock have been removed when extracting Phosphorus from the rock in a furnace. The end result is food grade, thermal phosphoric acid; however, for critical applications additional processing to remove arsenic compounds may be needed.

Wet phosphoric acid: Green phosphoric acid is prepared by adding sulfuric acid to calcium phosphate rock. While phosphoric acid has the potential to release three hydrogen ions, in aqueous solution the third requires a high pH because PO43− is almost as strong a base as hydroxide ion.

Through modern filtering techniques the wet process acid can be cleaned up significantly but still isn't as pure as thermal phosphoric acid; as it may contain other acidic species such as hydrofluoric acid.

Another technique is: 3H2SO4(aq) + Ca3(PO4)2(aq) + 6H2O(l) ↔ 2H3PO4(aq) + 3CaSO4(aq)+ 2H2O(l)

Answer 4

H3PO4 is prepared from “Puranal” grade orthophosphoric acid (min 85%) and “Puriss” grade phosphorous pentoxide or trade names of equivalent purity.

85% H3PO4 1200 ml
P2O5 2 lbs
H2O2 (30%) 5 ml
CrO3 50 - 100 mg
The phosphoric acid is poured into a 5 L beaker on a magnetic hotplate – stirrer inside a fume cupboard. Use a PTFE spinbar.


it is a good habit to write (aq) after the formula. ... If three H+ ions are added to phosphate, PO43-, phosphoric acid, H3PO4, is formed
PO43- is phosphate, and H3PO4 is phosphoric acid.

phosphoric acid n. A clear colorless liquid, H 3 PO 4 , used in fertilizers, ... It produces phosphoric anhydride which has an empirical formula P2O5

Answer 5

You make phosphoric acid from the oxide. Heating red phosphorus in excess oxygen gives you phosphorus pentoxide P4O10. Reacting P4O10 with water gives you phosphoric acid, H3PO4.

Answer 6

how do the Chinese make phosphorous acid from Dimethyl phosphite

Answer 7

H3 P O4