Question

Give the formula for each acid. a) hydrosulfuric acid b) phosphorous acid

Short answer

Hydrosulfuric acid is \( H_2S \); Phosphorous acid is \( H_3PO_3 \).

Step-by-step solution

Identify the Name and Type of Acid

First, we need to identify each acid's name and type from the problem statement. - **Hydrosulfuric acid**: This is a binary acid and does not contain any oxygen. The 'hydro-' prefix indicates the absence of oxygen. - **Phosphorous acid**: This is an oxyacid, which means it includes oxygen in the compound.

Write the Chemical Formula for Hydrosulfuric Acid

To write the formula for hydrosulfuric acid, we note that this acid consists of hydrogen and sulfur. The chemical equation is assembled as follows:- Hydrogen has a +1 charge: H⁺- Sulfur typically adopts a -2 charge: S²⁻To balance the charges, two hydrogens are needed for one sulfur, resulting in the formula:\[ H_2S \]

Write the Chemical Formula for Phosphorous Acid

The phosphorous acid consists of hydrogen, phosphorus, and oxygen. Its typical form is recognized as follows:- Phosphorous acid is known chemically as tri-hydrogen phosphite.The composition involves:- Three hydrogens (three +1 charges): H₃- One phosphorus: P- Three oxygen atoms, leading to a total ion charge: O₃The structural formula is represented as:\[ H_3PO_3 \]

Verify the Chemical Formulas

Finally, we should verify that the balance of charges and the identified number of atoms supports the acids' characteristics:- **Hydrosulfuric acid**: The formula \( H_2S \) confirms two positive charges from hydrogen and one negative charge from sulfur, creating a neutral compound.- **Phosphorous acid**: The formula \( H_3PO_3 \) maintains neutrality by having the combined charges of three hydrogens balancing with phosphite.

Key concepts

Binary Acids

Binary acids are one of the simplest forms of acids, consisting of only two different elements. Typically, these acids include hydrogen and one other non-metal element. A common feature you’ll notice in binary acid names is the 'hydro-' prefix. For example, in the case of hydrosulfuric acid, the 'hydro-' prefix signifies that the acid does not include oxygen.

The formula for binary acids follows a straightforward rule: the hydrogen ion (with a +1 charge) combines with the anion (which is negatively charged) to create a neutral compound. For example, hydrosulfuric acid combines two hydrogen ions and one sulfur ion to form the chemical compound \( H_2S \).

This reflects a key characteristic of binary acids: simplicity in structure, focusing on balancing the charges between hydrogen and the other element involved.

Oxyacids

Oxyacids introduce a different layer of complexity, as they are acids containing hydrogen, oxygen, and another element. The presence of oxygen distinguishes oxyacids from binary acids. This element is typically a non-metal and is central to the acid's properties. An example is phosphorous acid comprised of hydrogen, phosphorus, and oxygen.

In creating the formula for an oxyacid like phosphorous acid (\( H_3PO_3 \)), the oxygen tends to bond with the central atom, forming a polyatomic ion such as phosphite. The composition of such acids generally includes both -OH (hydroxide) groups and less easily ionized oxygen atoms.

Oxyacids are known for their role in oxidation-reduction reactions and as intermediates in chemical processes, and they display greater complexity and variety compared to binary acids.

Chemical Charges

Chemical charges are crucial to forming stable compounds, including acids. Each atom or ion carries a specific charge that determines how it will interact with other elements. For example, hydrogen ions always carry a positive charge (+1), denoted as \( H^+ \), while other non-metal ions like sulfur may carry a negative charge (-2), as in the case of \( S^{2-} \).

In both binary and oxyacids, the charges must balance to form a neutral compound. This means the total positive charge must equal the total negative charge. Therefore, to create a stable molecule of hydrosulfuric acid (\( H_2S \)), two hydrogen ions are needed to balance the -2 charge of one sulfur ion.

Understanding chemical charges is essential to deducing the correct chemical formulas and ensuring that compounds are neutrally charged.

Neutral Compounds

Neutral compounds display a balanced set of positive and negative charges, resulting in no overall charge. This balance is maintained through careful combinations of ions or atoms.

Taking the example of acids, a compound like hydrosulfuric acid (\( H_2S \)) is considered neutral because the two positively charged hydrogen ions offset the negatively charged sulfur ion.

Similarly, phosphorous acid (\( H_3PO_3 \)) balances three hydroxide ions (each carrying -1 charge) with three hydrogen ions.

Neutrality in compounds plays a crucial role in their stability and reactivity. Without neutral charges, substances would be overly acidic or basic, destabilizing the chemical reactions they partake in.