Acids, bases and pH

siiky

2023/07/28

2023/07/28

2023/07/28

science,chemistry

Svante Arrhenius's definition of acids/bases

Acids increace the concentration of H+ (protons) when in an aqueous solution; bases increase the concnetration of OH- when in an aqueous solution.

Bronsted-Lowry definition of acids/bases

Acids donate protons (H+); bases accept protons (H+).

Examples

HCl (aq) -> H+ (aq) + CL- (aq)

NaOH (aq) -> Na+ (aq) + OH- (aq)

From this we can conclude that HCl is an acid, and that NaOH is a base.

Definition of pH

pH = -log10 [H+] = -log10 [H3O+] (where [H+]/[H3O+] is the concentration of H+/H3O+)

Assuming [H+] is 10^-7 M for pure (distilled) water, 10^-4 M for orange juice, and 10^-12 M for bleach: water's pH is -log10(10^-7) = -(-7) = 7; orange juice's pH is 4; and bleach's pH is 12.