Final answer:
Sodium hydroxide, potassium hydroxide, and calcium hydroxide are strong bases that can remove a proton from formic acid, favoring product formation; whereas, ammonium hydroxide is less effective due to being a weaker base.
Step-by-step explanation:
The given question asks which base can remove a proton from formic acid in a reaction that favors products. The bases listed are all capable of acting as proton acceptors. Formic acid, being an acid itself, will react with strong bases to form water and a salt. Bases like sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2) are strong bases and contain the hydroxide ion (OH−), which accepts a proton from acids to form water. On the other hand, the ammonium hydroxide (NH4+OH) exists in equilibrium with ammonia and water, and it is not as strong a base as the others mentioned.
Therefore, sodium hydroxide, potassium hydroxide, and calcium hydroxide are all suitable to remove a proton from formic acid in a reaction that will favor the formation of products, such as the corresponding formate salt and water. Ammonium hydroxide is also capable but less effective compared to the strong bases listed. The reaction moves towards completion with strong bases due to the levelling effect.