Which species is classified as an Arrhenius base?

Which species is classified as an Arrhenius base?

• A. CH3OH
• B. PO4-3
• C. LiOH
• D. CO3-2

Answer: (C)

Arrhenius bases are substances that increase the concentration of hydroxide ions (OH−) in water by dissociating to release OH−. Lithium hydroxide does this directly: it dissociates into Li+ and OH−, adding OH− to the solution and making the solution basic. The other options do not supply OH− in their formula: methanol is a neutral molecule that doesn’t release hydroxide in water, while carbonate and phosphate ions can act as bases in other ways (such as accepting protons or undergoing hydrolysis) but they don’t inherently provide OH− when dissolved. Hence, lithium hydroxide is the Arrhenius base in this set.

Arrhenius bases are substances that increase the concentration of hydroxide ions (OH−) in water by dissociating to release OH−. Lithium hydroxide does this directly: it dissociates into Li+ and OH−, adding OH− to the solution and making the solution basic. The other options do not supply OH− in their formula: methanol is a neutral molecule that doesn’t release hydroxide in water, while carbonate and phosphate ions can act as bases in other ways (such as accepting protons or undergoing hydrolysis) but they don’t inherently provide OH− when dissolved. Hence, lithium hydroxide is the Arrhenius base in this set.