Individual solutions of Ba(OH)2 and H2SO4 both conduct electricity, but the conductivity disappears when equal molar amounts of the solutions are mixed. Explain.

Verified step by step guidance

1. Recognize that Ba(OH)2 and H2SO4 are strong electrolytes, meaning they completely dissociate into ions in solution. Ba(OH)2 dissociates into Ba^{2+} and 2OH^{-}, while H2SO4 dissociates into 2H^{+} and SO4^{2-}.
2. Understand that when these solutions are mixed in equal molar amounts, a neutralization reaction occurs. The hydroxide ions (OH^{-}) from Ba(OH)2 react with the hydrogen ions (H^{+}) from H2SO4 to form water (H2O).
3. Write the balanced chemical equation for the reaction: Ba(OH)2 + H2SO4 ightarrow BaSO4 + 2H2O. This shows that barium sulfate (BaSO4) and water are formed.
4. Note that BaSO4 is an insoluble salt and precipitates out of the solution. This removes Ba^{2+} and SO4^{2-} ions from the solution, which were contributing to the conductivity.
5. Conclude that the disappearance of conductivity is due to the removal of free ions from the solution. The formation of water (which does not conduct electricity) and the precipitation of BaSO4 (which removes ions from the solution) result in a decrease in the number of charge carriers, thus reducing conductivity.

Key Concepts

Electrolytes and Conductivity

Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity. Strong electrolytes, like Ba(OH)2 and H2SO4, fully dissociate into their constituent ions, which facilitates electrical conductivity. The presence of free-moving ions in solution is essential for conducting electricity.

Neutralization Reaction

A neutralization reaction occurs when an acid reacts with a base to form water and a salt. In this case, H2SO4 (an acid) reacts with Ba(OH)2 (a base) to produce BaSO4 (a salt) and water. This reaction consumes the ions responsible for conductivity, leading to a decrease in the solution's ability to conduct electricity.

Ionic Strength and Ion Pairing

Ionic strength refers to the concentration of ions in a solution, which can affect the behavior of ions, including their ability to conduct electricity. When Ba(OH)2 and H2SO4 are mixed, the formation of BaSO4 precipitate reduces the number of free ions in solution. Additionally, ion pairing can occur, where ions associate and reduce the number of free-moving charge carriers, further diminishing conductivity.