Phosphoric acid, also known as orthophosphoric acid, is a mineral acid with the chemical formula H3PO4. It is a clear, colorless liquid that is widely used in various industries, including pharmaceuticals, fertilizers, and food production. Understanding the oxidation state of phosphoric acid requires examining the oxidation state of each element present in the compound.

Phosphorus Oxidation State:
The central atom in phosphoric acid is phosphorus (P). To determine its oxidation state, we consider that hydrogen (H) has an oxidation state of +1 and oxygen (O) has an oxidation state of -2. Since there are three hydrogen atoms and four oxygen atoms in phosphoric acid, the overall charge of the compound is zero.

Given that the sum of the oxidation states of all the atoms in a compound must equal its charge, we can calculate the oxidation state of phosphorus as follows:

(3 x +1) + (4 x -2) = 0
3 + (-8) = 0
-5 = 0

Therefore, the oxidation state of phosphorus in phosphoric acid is +5.

Explanation:
The oxidation state of an element refers to the charge it would have if all the shared electrons in a compound were assigned to the more electronegative atom. In phosphoric acid, the oxygen atoms are more electronegative than phosphorus, so we assign all the shared electrons to oxygen.

Phosphoric acid consists of three hydroxyl groups (-OH) attached to a central phosphorus atom. Each hydroxyl group contributes a -1 charge, resulting in a total charge of -3. Since the overall charge of the compound is zero, the phosphorus atom must have an oxidation state of +5 to balance the negative charge.

Summary:
In summary, the oxidation state of phosphorus in phosphoric acid is +5. This is determined by considering the oxidation states of hydrogen and oxygen in the compound and applying the principle that the sum of the oxidation states must equal the compound's charge. The oxidation state of +5 indicates that phosphorus has lost five electrons and has a positive charge of 5.