Problem 46 - Chemistry: An Atoms-Focused Approach

Question

Hydrogen chloride and water are molecular compounds, yet a solution of HCl dissolved in \(\mathrm{H}_{2} \mathrm{O}\) is an excellent conductor of electricity. Explain why.

Step-by-Step Solution

Answer

A solution of hydrogen chloride (HCl) dissolved in water is an excellent conductor of electricity because of the ionization process that occurs when HCl dissolves in water. This process results in the formation of positively charged hydronium ions (H₃O⁺) and negatively charged chloride ions (Cl⁻), which can move freely through the solution and carry electric charges. Although HCl is a molecular compound, its interaction with water leads to ion formation, enabling the resulting solution to conduct electricity efficiently.

Step 1: Molecular compounds are formed by the sharing of electrons between non-metal atoms, resulting in the formation of covalent bonds. Unlike ionic compounds, they do not generally dissociate into ions when dissolved in water. As a result, they typically do not conduct electricity when dissolved in water, as there are no ions to carry the electric charge. #Step 2: Hydrogen chloride (HCl) in water#

HCl is a molecular compound, but when it dissolves in water, there is a strong interaction between the hydrogen and chlorine atoms of HCl and the oxygen and hydrogen atoms of water molecules. This interaction results in the so-called ionization of HCl, whereby HCl molecules break apart and form ions in the solution. #Step 3: Ionization of HCl in water#

Step 2: The ionization of HCl in water produces two types of ions: (1) positively charged hydrogen ions (protons) represented as \(\mathrm{H}^{+}\), and (2) negatively charged chloride ions, represented as \(\mathrm{Cl}^{–}\). The ionization of HCl in water can be presented by the following equation: HCl + H\(_2\)O \(\longrightarrow\) H\(_3\)O\(^+\) + Cl\(^-\) The reaction shows the transfer of proton (H\(^+\)) from HCl to a water molecule, forming hydronium ion (H\(_3\)O\(^+\)) and chloride ion (Cl\(^-\)) in the solution. #Step 4: Conductivity of HCl solution#

As HCl dissolves in water and ionizes to form positively charged hydronium ions and negatively charged chloride ions, it creates a solution with a high concentration of mobile charge carriers. These ions can move freely through the solution, allowing electric charges to be transferred from one point to another. This results in the HCl solution being an excellent conductor of electricity. In conclusion, the reason why an HCl solution in water is an excellent conductor of electricity is the ionization process that occurs when HCl dissolves in water, producing a significant amount of ions that can carry electric charges through the solution. Even though HCl is a molecular compound, its interaction with water leads to ion formation, which enables the resulting solution to conduct electricity efficiently.