To determine which is the strongest acid in aqueous solution among the given options, let's analyze the chemical properties and behavior of each compound:
A. HCl (Hydrochloric acid):
- HCl is a strong acid. In aqueous solution, it completely dissociates into H⁺ and Cl⁻ ions. This results in a high concentration of hydrogen ions in the solution, making it a very strong acid.
B. H₂S (Hydrosulfuric acid or Hydrogen sulfide):
- H₂S is considered a weak acid. It partially dissociates in water, producing a relatively lower concentration of hydrogen ions compared to strong acids.
C. SiH₄ (Silane):
- SiH₄ does not dissociate in water and is not considered an acid. It is a neutral molecule with no acidic properties in an aqueous solution.
D. PH₃ (Phosphine):
- Similar to SiH₄, PH₃ does not dissociate in water and does not exhibit acidic behavior. It is also neutral in an aqueous solution.
Based on this analysis, the compound that is identified as the strongest acid in aqueous solution from the given options is:
A. HCl
So, the correct answer is:
A. HCl
