Question

Give the IUPAC systematic name for each of the following ternary oxyacids: (a) \(\mathrm{HClO}_{2}(a q)\) (b) \(\mathrm{H}_{3} \mathrm{PO}_{4}(a q)\)

Short answer

(a) Chlorous acid; (b) Phosphoric acid.

Step-by-step solution

Identify the central element and its oxidation state

For each oxyacid, identify the central element (non-metal) and then determine its oxidation state. This helps in naming the acid according to IUPAC conventions. (a) The central element in HClO₂ is chlorine (Cl). Let the oxidation state of Cl be 'x'. Writing the equation for oxidation states: H: +1, Cl: x, O: -2 each; thus, 1(x) + 2(-2) + 1(+1) = 0 So, x - 4 + 1 = 0 Therefore, x = +3. (b) The central element in H₃PO₄ is phosphorus (P). Let the oxidation state of P be 'y'. Writing the equation for oxidation states: H: +1 each, P: y, O: -2 each; thus, y + 4(-2) + 3(+1) = 0 So, y - 8 + 3 = 0 Therefore, y = +5.

Assign the IUPAC name based on oxidation state

Using the oxidation state determined, assign the systematic name following IUPAC nomenclature rules for oxyacids. (a) Since the oxidation state of chlorine is +3, and considering that it's an oxygenated acid of chlorine, the IUPAC name is chlorous acid, written as 'chlorous acid.' (b) With phosphorus at an oxidation state of +5 and noting it's an oxygenated acid of phosphorus, the IUPAC name is phosphoric acid, which is written as 'phosphoric acid.'

Verify IUPAC naming conventions

Consult the IUPAC rules to confirm that the assigned names match the standard nomenclature. - The use of suffixes '-ous' and '-ic' are consistent, with chlorous acid denoting HClO₂ and phosphoric acid denoting H₃PO₄ in standard naming conventions.

Key concepts

IUPAC Naming

IUPAC Naming is an essential system used worldwide for the standardization of chemical nomenclature. It allows chemists to communicate compounds' identities clearly and unambiguously. In the case of oxyacids like

• each oxyacid, identifying the central element and its oxidation state is the first step.
• For HClO₂, the central element is chlorine (Cl), while for H₃PO₄, it is phosphorus (P).

These central elements bond with hydrogen and oxygen to form the oxyacids. Based on the oxidation state of the central element, we can determine the name of the acid according to IUPAC nomenclature rules:

• "-ous" is used if the central element has a lower oxidation state, resulting in names like chlorous acid for HClO₂.
• "-ic" is used for a higher oxidation state, forming names like phosphoric acid for H₃PO₄.

This systematic approach ensures no confusion over the chemical's nature, even across language barriers.

Oxidation States

Oxidation states, or oxidation numbers, reflect how electrons are distributed in a compound, which is critical for IUPAC naming conventions. By determining the oxidation state, you can infer how many electrons are gained or lost by elements during chemical reactions. For oxyacids, the central element's oxidation state is derived by writing the equation based on known oxidation states of hydrogen and oxygen. For HClO₂, the chlorine atom carries an oxidation state of +3. In the case of H₃PO₄, phosphorus is at +5. This information not only dictates the IUPAC name, but also can help predict reactivity and stability. Using these numbers efficiently helps chemists play MadLibs with science, filling in unknown elements with confidence and precision.

Oxyacids

Oxyacids are vital components within chemistry, characterized by their composition of hydrogen, oxygen, and another non-metallic element. These compounds release hydrogen ions when dissolved in water, making them acidic. Understanding the composition and naming of oxyacids is especially important in chemical nomenclature. The oxyacids form a particular pattern when going from lower to higher oxidation states at which the central element is oxidized.

• For example, if chlorine is bonded to oxygen, it forms different oxyacids based on its oxidation state, such as chlorous acid in HClO₂.
• Similarly, phosphorus forms phosphoric acid as seen in H₃PO₄.

Mastering the concept of oxyacids not only aids in proper IUPAC naming but also in grasping broader concepts of acid strength and behavior in water. These intricate details help build a deeper understanding of both physical and theoretical chemistry.