According to the Arrhenius definition, acids are substances that increase the concentration of hydrogen ions (H⁺) when dissolved in water. Given this definition, let's analyze each compound from the list to determine which are acids.
1. HBr (Hydrobromic Acid):
- When HBr dissolves in water, it dissociates to form H⁺ ions and Br⁻ ions.
- Since it increases the concentration of H⁺ ions, HBr is an acid.
2. [tex]$Sr(OH)_2$[/tex] (Strontium Hydroxide):
- When [tex]$Sr(OH)_2$[/tex] dissolves in water, it dissociates to form Sr²⁺ ions and OH⁻ ions.
- Since it increases the concentration of OH⁻ ions rather than H⁺ ions, [tex]$Sr(OH)_2$[/tex] is a base, not an acid.
3. HClO (Hypochlorous Acid):
- When HClO dissolves in water, it dissociates to form H⁺ ions and ClO⁻ ions.
- Since it increases the concentration of H⁺ ions, HClO is an acid.
4. [tex]$H_2S$[/tex] (Hydrosulfuric Acid):
- When [tex]$H_2S$[/tex] dissolves in water, it dissociates to form H⁺ ions and HS⁻ ions.
- Since it increases the concentration of H⁺ ions, [tex]$H_2S$[/tex] is an acid.
5. LOH:
- LOH is not a standard chemical formula and doesn't correspond to a known acid or base.
- Without additional context or information, it cannot be identified as an acid, so it is excluded from the list of acids.
In summary, the acids from the given list are:
- HBr
- HClO
- [tex]$H_2S$[/tex]
So, the correct choices are:
- HBr
- HClO
- [tex]$H_2S$[/tex]
