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In an acid-base titration, the equivalence point is a critical moment. It is reached when the amount of acid equals the amount of base in a solution. This does not mean the solution is neutral. Whether it is acidic, basic, or neutral depends on the strengths of the reacting acid and base.
In the given exercise, the base is sodium hydroxide (NaOH), a strong base, and the acid is formic acid (HCO鈧侶), a weak acid. When they react, NaOH completely ionizes, while formic acid only partially ionizes because it is weak.
At the equivalence point, all of the NaOH has reacted with HCO鈧侶 to form water and the conjugate base of the weak acid, formate ion (HCO鈧傗伝). Since the conjugate base is left in the solution, the solution becomes basic after the equivalence point is reached.

An acid-base titration is a laboratory technique used to determine the concentration of an unknown acid or base. The process involves adding a titrant to a solution until the reaction reaches the equivalence point.
Key steps in titration include determining the point where the added titrant has completely reacted with the solution in the flask. For accuracy, it is essential to understand the nature of the acid and base involved.

• For strong acids and strong bases, the equivalence point corresponds to a neutral pH.
• For weak acids and strong bases, like formic acid with NaOH, the equivalence point tends to be in the basic range.
• Indicators or pH meters can be used to detect the equivalence point visually or electronically.

In this exercise, we are dealing with formic acid and NaOH, where the resultant solution is basic even at the equivalence point.

A weak acid is an acid that does not completely dissociate in water. Formic acid ( HCO鈧侶) is a prime example. Its dissociation into hydrogen ions (H鈦�) and formate ions (HCO鈧傗伝) is partial, meaning only some of the molecules will ionize.
We measure the strength of an acid using the acid dissociation constant ( K鈧�), which indicates how much of the acid ionizes. For formic acid, this value is small ( 1.8 脳 10鈦烩伌), confirming it is a weak acid.
In the context of titration, when a weak acid reacts with a strong base, the base consumes nearly all the hydrogen ions available from the weak acid. This leads to the formation of more of the weak acid's conjugate base, resulting in a basic solution at the equivalence point.

A strong base is fully ionized in water. Sodium hydroxide ( NaOH) is a classic strong base, which means it completely dissociates into sodium ions (Na鈦�) and hydroxide ions (OH鈦�).
Because strong bases fully dissociate, they effectively neutralize acids during a titration process. They react completely with the hydrogen ions from acids, including weak ones, transforming them into water and the salt of the weak acid.
In our exercise, the strong base, NaOH, fully reacts with formic acid, leaving formate ions, which create a basic environment. The strong nature of NaOH ensures that it can drive the ionization process to completion even when the reacting acid is weak.