Question

State the suffix in the name for each of the following: (a) \(\mathrm{Na}_{2} \mathrm{~S}\) (b) \(\mathrm{H}_{2} \mathrm{~S}(a q)\)

Short answer

(a) The suffix for Na₂S is '-sulfide'. (b) The suffix for H₂S(aq) is '-ic acid'.

Step-by-step solution

Understanding the Compound Name for Na₂S

The compound Na₂S is sodium sulfide. In ionic compounds, the suffix '-ide' is used for the non-metal element in the name. Since the non-metal here is sulfur, the suffix in this compound is '-sulfide'.

Recognizing the Acidic Nature of H₂S(aq)

H₂S(aq) is known as hydrosulfuric acid. When hydrogen is bonded with a non-metal and the solution is aqueous, the compound is recognized as an acid. Typically, the suffix '-ic acid' is added to the root name of the non-metal when it forms a binary acid (hydro + base name + ic acid). Here, the suffix is '-ic acid'.

Key concepts

Ionic Compounds

Ionic compounds are made up of positive and negative ions that bind together due to attraction between opposite charges. In general, they consist of metals and non-metals. The metal ion loses electrons to form a positive ion, while the non-metal gains electrons to form a negative ion. For example, in sodium sulfide (\(\mathrm{Na}_{2} \mathrm{~S}\)), sodium (\(\mathrm{Na}\)) acts as the metal ion that donates electrons, becoming \(\mathrm{Na}^{+}\), and sulfur (\(\mathrm{S}\)) as the non-metal that gains these electrons, becoming \(\mathrm{S}^{2-}\). This electron transfer results in the formation of \(\mathrm{Na}_{2} \mathrm{~S}\), an ionic compound.It's crucial to know that ion combinations determine the name of ionic compounds, which typically use the suffix '-ide' for the non-metal. Hence, \(\mathrm{Na}_{2} \mathrm{~S}\) is known as sodium sulfide.

Acid Naming

Acids are special types of compounds defined by their ability to donate protons (\(\mathrm{H}^{+}\)) in an aqueous solution. When it comes to naming acids, it's essential to understand the type of acid you're dealing with. The acid naming rules vary depending on whether you have a binary acid or an oxyacid.

• Binary Acids: These are composed of hydrogen and one other non-metal. The naming convention involves using the prefix 'hydro' followed by the root name of the non-metal modified with the suffix '-ic acid'. For instance, hydrosulfuric acid is the name for \(\mathrm{H}_{2} \mathrm{~S}(aq)\).
• Oxyacids: Contain hydrogen, oxygen, and another element. Their naming generally involves changing the end of the polyatomic ion from '-ate' to '-ic acid' or from '-ite' to '-ous acid'.

Knowing whether a solution is aqueous affects naming. An aqueous solution means it is dissolved in water, making it an acid by nature—this transformation is why \(\mathrm{H}_{2} \mathrm{~S}(aq)\) is not just a gas, but hydrosulfuric acid.

Sulfide Suffix

The suffixes used in chemical nomenclature help identify the type of compound, especially when dealing with sulfur, which can form various compounds. For sulfide, the sulfur atom acts as the non-metal component in an ionic compound, capturing electrons from a metal.The suffix '-sulfide' is particularly important in cases where sulfur combines with elements to form basic ionic compounds. It signifies that the compound is an ionic compound with sulfur acting as the anion. For instance, sodium sulfide (\(\mathrm{Na}_{2} \mathrm{~S}\)) uses the suffix '-sulfide' because sulfur accepts electrons becoming an ion in the compound. Understanding such suffixes aids in proper chemical naming and communication in chemistry.