Question

Provide the formula for each acid. a. phosphoric acid b. hydrocyanic acid c. chlorous acid

Short answer

a. Phosphoric acid: \(H_3PO_4\), b. Hydrocyanic acid: \(HCN\), c. Chlorous acid: \(HClO_2\).

Step-by-step solution

Identify the Elements in Phosphoric Acid

Phosphoric acid contains phosphorus, hydrogen, and oxygen. In chemistry, its formula is commonly derived based on the knowledge that phosphoric acid is a triprotic acid (able to donate three protons), and its general formula is \(H_nPO_4\bar{n}\), where n is 3.

Write the Chemical Formula for Phosphoric Acid

Considering the trivalent nature of phosphorus in phosphoric acid, the chemical formula is \(H_3PO_4\).

Identify the Elements in Hydrocyanic Acid

Hydrocyanic acid consists of hydrogen, carbon, and nitrogen. It is a weak acid and its general formula is derived from the knowledge that it contains one hydrogen atom, one carbon atom, and one nitrogen atom.

Write the Chemical Formula for Hydrocyanic Acid

Given that it is made of hydrogen, carbon, and nitrogen, the formula for hydrocyanic acid is \(HCN\).

Identify the Elements in Chlorous Acid

Chlorous acid is an acid containing chlorine, hydrogen, and oxygen. The name 'chlorous' indicates the chlorine is in a \(+3\) oxidation state and the acid contains one more oxygen than a hypo- acid but one less than -ic acid. Its general formula reflects that the acid has one chlorine, one hydrogen, and typically two oxygen atoms.

Write the Chemical Formula for Chlorous Acid

Taking into account the characteristics of chlorous acid, its chemical formula is \(HClO_2\).

Key concepts

Phosphoric Acid Formula

Phosphoric acid is a common inorganic acid that plays a role in several applications, from fertilizer production to food flavoring.
Its chemical formula is \(H_3PO_4\), which reflects its composition of three hydrogen atoms, one phosphorus atom, and four oxygen atoms. Understanding phosphoric acid's formula is crucial in considering its triprotic nature, meaning it can donate three hydrogen ions (\(H^+\)) when dissolved in water.
As a triprotic acid, it provides multiple hydrogen ions in a stepwise manner, making it a key acid to study when learning about pH and acid-base reactions.

Hydrocyanic Acid Formula

Hydrocyanic acid, also known as prussic acid, is a notably simple yet highly toxic acid. With the chemical formula \(HCN\), it consists of only one hydrogen, one carbon, and one nitrogen atom.
Its simplicity can be deceptive, as \(HCN\) in its gaseous form is extremely poisonous. In aqueous solutions, hydrocyanic acid is weak, meaning it does not fully dissociate to release a large number of hydrogen ions. This characteristic is essential when discussing the strength and potential risks associated with different acids.

Chlorous Acid Formula

Chlorous acid is a lesser-known acid with a formula of \(HClO_2\). This acid contains one hydrogen, one chlorine, and two oxygen atoms.
The oxidation state of chlorine in this acid is +3, which places it between hypochlorous acid (\(HClO\), with chlorine at +1) and chloric acid (\(HClO_3\), where chlorine is at +5). Unlike hydrochloric acid (\(HCl\)), chlorous acid is not a strong acid, and it's more commonly referred to when discussing various oxidation states of chlorine-containing compounds.

Triprotic Acid

The concept of a triprotic acid is vital in understanding acids that can donate three protons or hydrogen ions in a solution. Phosphoric acid (\(H_3PO_4\)) exemplifies a triprotic acid.
These acids undergo a stepwise dissociation, releasing one proton at a time, each step characterized by its own equilibrium constant. This process influences the behavior of these acids in various chemical reactions. Triprotic acids are key in advanced topics of acid-base chemistry, buffering systems, and titration analyses.

Chemical Nomenclature

Chemical nomenclature is the systematic way of naming chemical substances. It ensures consistency and clarity across the scientific community when referring to compounds. When applying chemical nomenclature to acids, specific rules are followed.
For instance, acids like \(HClO_2\) are named by identifying the central atom (chlorine), the oxidation state (chlorous for +3), and the type of compound (acid). Understanding these principles is crucial when learning chemistry, as it allows for the accurate communication and understanding of chemical substances.