Question

Write formulas for these acids: (a) acetic acid (d) boric acid (b) hydrofluoric acid (e) nitrous acid (c) hydrosulfuric acid (f) hypochlorous acid

Short answer

Formulas: (a) CH3COOH, (d) H3BO3, (b) HF, (e) HNO2, (c) H2S, (f) HClO.

Step-by-step solution

Acetic Acid Formula

Acetic acid, also known as ethanoic acid, has the formula CH3COOH. It contains a methyl group (CH3-) attached to a carboxyl group (COOH).

Boric Acid Formula

Boric acid is represented by the formula H3BO3. This compound consists of a boron (B) atom connected by single bonds to three hydroxyl groups (OH).

Hydrofluoric Acid Formula

The chemical formula for hydrofluoric acid is HF. It is composed of one hydrogen atom bonded to a fluorine atom.

Nitrous Acid Formula

Nitrous acid has the formula HNO2. It is constructed from one nitrogen atom double-bonded to an oxygen atom, and single-bonded to a hydroxyl group (OH), and another oxygen atom.

Hydrosulfuric Acid Formula

Hydrosulfuric acid is denoted by the formula H2S. The structure features two hydrogen atoms each bonded to a central sulfur atom.

Hypochlorous Acid Formula

The formula of hypochlorous acid is HClO. This consists of one hydrogen atom bonded to a chlorine atom, which is also bonded to an oxygen atom.

Key concepts

Understanding Acetic Acid

Acetic acid, commonly known in household settings as vinegar, is a fundamental organic acid used in a variety of industrial and culinary applications. At a molecular level, the acetic acid formula is represented as (CH3COOH). This structure is comprised of a methyl group ((CH3)) which serves as a hydrogen carbon chain connected to a carboxyl group ((COOH)), responsible for its acidic properties.

• Acetic acid is widely used as a preservative in food products due to its antibacterial properties.
• It also has applications in the production of plastics, pharmaceuticals, and other chemicals.
• The presence of the carboxyl group in acetic acid is what makes it part of the carboxylic acids family, which are known for their typically pungent odors and corrosive properties.

Its ability to donate a proton ((H+)) in an aqueous solution is what classifies it as an acid, following the Bronsted-Lowry definition. The carboxyl group is also key for the formation of esters and other derivatives, making acetic acid a versatile and important chemical in organic synthesis.

Properties of Boric Acid

Boric acid is distinguished from many other acids by its unique formula (H3BO3), and its occurrence in nature as a mineral called sassolite. In boric acid:

• The boron atom ((B)) is central, coordinating with three hydroxyl groups ((OH)), forming a trigonal planar geometry.
• This substance is often used as an antiseptic, insecticide, flame retardant, neutron absorber, or as a precursor to other chemical compounds.
• The mild acidity of boric acid arises from the boron atom’s ability to accept an electron pair, while a hydroxyl group can lose a hydrogen ion ((H+)).

Boric acid thus acts as a Lewis acid, rather than a Bronsted-Lowry acid. Its weak acidic nature and low toxicity make it suitable for various low-hazard applications in daily life, such as in eye drops or mild antiseptics.

Exploring Hydrofluoric Acid

Hydrofluoric acid is known for its distinct behavior and formula, (HF). Notably, it is:

• Less acidic compared to other hydrohalic acids, yet it is extremely corrosive to organic tissues and materials.
• Used in industrial applications such as glass etching, metal cleaning, and in the production of fluorocarbons.
• Composed of one hydrogen atom ((H)) bonded to a fluorine atom ((F)), which gives it unique properties due to the high electronegativity and small size of the fluorine atom.

The bond in hydrofluoric acid is polar, allowing for the attraction between the positively charged hydrogen and negatively charged fluorine, a characteristic that contributes to its high reactivity. Safety precautions are vital when handling hydrofluoric acid due to its potential to cause severe burns upon contact with skin.

Nitrous Acid and Its Reactions

Represented by the formula (HNO2), nitrous acid is a weaker acid known for its participation in various chemical reactions:

• It consists of a nitrogen atom ((N)) double-bonded to an oxygen atom ((O)), and single-bonded to an hydroxyl group ((OH)), and another oxygen atom.
• Nitrous acid is often used in situ or generated as needed because it is unstable at room temperature.
• It plays a significant role in the atmospheric chemistry of nitrogen oxides, as well as in organic chemistry as a nitrosating agent.

Nitrous acid is commonly encountered in the form of its salts, such as sodium nitrite((NaNO2)), which have various applications, including the preservation of food. The acid itself can decompose to form nitrogen dioxide ((NO2)), nitric oxide ((NO)), and water, illustrating its tendency for decomposition in the presence of light, heat, or alkaline conditions.

Hydrosulfuric Acid Characteristics

Hydrosulfuric acid is denoted by the formula (H2S) and is often confused with sulfuric acid ((H2SO4)); however, it presents different chemical properties:

• It is characterized by the presence of two hydrogen atoms ((H)) bonded to a singular sulfur atom ((S)), forming a gaseous compound under standard conditions.
• Although not a strong acid, it is notable for its rotten egg smell and its toxicity, which can be lethal in high concentrations.
• Hydrosulfuric acid has applications in the production of sulfur compounds and can be found naturally in volcanic gases and some mineral waters.

Due to its ability to act as both a reducing agent and a weak acid, it finds utility in various chemical reactions. Despite these important uses, caution is necessary when dealing with hydrosulfuric acid due to its poisonous nature.

Hypochlorous Acid as a Disinfectant

The formula for hypochlorous acid is given as (HClO), with an interesting use as an effective disinfectant:

• It is formed by the bonding of hydrogen ((H)), chlorine ((Cl)), and oxygen ((O)) atoms.
• Recognized for its role in the human immune system as the active substance of white blood cells.
• Commercially, it is generated through the electrolysis of saltwater and is employed in water treatment, wound care, and sanitizing applications due to its potent antimicrobial properties.

Hypochlorous acid is preferable in many cleaning contexts as it is less harmful than its counterparts, such as chlorine bleaches. It efficiently eliminates bacteria, viruses, and fungi upon contact, indicating its capability as a sanitizer while being non-toxic to humans.