Problem 59 - Chemistry The Molecular Science

Question

Give the correct name for each compound. (a) \(\mathrm{HBr}\) (b) \(\mathrm{ClF}_{3}\) (c) \(\mathrm{Cl}_{2} \mathrm{O}_{7}\) (d) \(\mathrm{BI}_{3}\)

Step-by-Step Solution

Answer

(a) Hydrobromic acid, (b) Chlorine trifluoride, (c) Dichlorine heptoxide, (d) Boron triiodide.

Step 1: Naming Binary Acids

For binary acids like \( \mathrm{HBr} \), the name is derived from the non-metal element followed by the word 'acid.' Since the non-metal in \( \mathrm{HBr} \) is bromine, the compound is named as hydrobromic acid.

Step 2: Naming Molecular Compounds

\( \mathrm{ClF}_{3} \) is a molecular compound composed of chlorine and fluorine. It is named using the prefix system: the prefix 'tri-' for the three fluorine atoms gives us the name chlorine trifluoride.

Step 3: Naming Higher Oxides

\( \mathrm{Cl}_{2} \mathrm{O}_{7} \) is a higher oxide of chlorine. It is named using numerical prefixes: 'di-' for two chlorine atoms and 'hepta-' for seven oxygen atoms, resulting in the name dichlorine heptoxide.

Step 4: Naming Other Binary Compounds

\( \mathrm{BI}_{3} \) is a binary compound containing boron and iodine. It is named using the prefix 'tri-' for the three iodine atoms, thus the name boron triiodide.

Key Concepts

Binary Acids

Binary acids are a specific class of acids that contain two elements: hydrogen and a non-metal. These acids are typically composed in solutions as aqueous. In naming them, the distinction lies in the presence of hydrogen bonded to a non-metal. The usual formula for binary acids includes the hydrogen atom followed by the non-metal. To name a binary acid, prefix the root name of the non-metal with 'hydro-' and add 'ic' to the end, then conclude with the word 'acid'.
For example, the binary acid formed with hydrogen and bromine is named hydrobromic acid, denoted as \( \mathrm{HBr} \). This name signifies to chemists that hydrogen is bonded to a bromine atom in aqueous solution, delivering properties typical of binary acids.

Molecular Compounds

Molecular compounds are formed when two non-metals combine. The most common method for naming involves using prefixes to indicate the number of each type of atom present in the compound. These prefixes include mono-, di-, tri-, tetra-, penta-, hexa- and so on.
The compound \( \mathrm{ClF}_{3} \), for instance, consists of one chlorine atom and three fluorine atoms. Hence, it is named chlorine trifluoride. Here, 'tri-' signals the presence of the three fluorine atoms, while 'chlorine' indicates the non-metal primary component. These prefixes help in representing the exact makeup of the compound.

Higher Oxides

Higher oxides refer to compounds where an element is bonded to a higher quantity of oxygen. It is common in non-metals, especially in groups such as chlorine, sulfur, or nitrogen. In naming these compounds, prefixes are vital for highlighting the number of atoms in the formula.
For instance, \( \mathrm{Cl}_{2} \mathrm{O}_{7} \) is a higher oxide. It is denoted as dichlorine heptoxide. The prefix 'di-' indicates the presence of two chlorine atoms, while 'hepta-' indicates the presence of seven oxygen atoms. These naming conventions are crucial for differentiating among the various oxides and understanding their structure and properties.

Binary Compounds

Binary compounds consist of two different elements. Typically, these include a metal and a non-metal or two non-metals. In the case of non-metals, prefixes are used to specify the number of atoms.
For example, the compound \( \mathrm{BI}_{3} \) consists of boron and iodine. Following the rules of naming binary compounds, it is called boron triiodide. The 'tri-' prefix is essential because it indicates the presence of three iodine atoms, while 'boron' points to the other element involved. Proper naming aids in distinguishing the numerous binary compounds present and understanding their chemical identities.