Two 20.0-mL samples, one 0.200 M KOH and the other 0.200 M CH₃NH₂, are titrated with 0.100 M HI. a. What is the volume of added acid at the equivalence point for each titration?

Verified step by step guidance

1. Identify the reaction for each titration: KOH with HI and CH_3NH_2 with HI.
2. For KOH, the reaction is: KOH + HI \rightarrow KI + H_2O. Calculate moles of KOH: \text{moles} = 0.200 \text{ M} \times 0.0200 \text{ L}.
3. For CH_3NH_2, the reaction is: CH_3NH_2 + HI \rightarrow CH_3NH_3^+I^-. Calculate moles of CH_3NH_2: \text{moles} = 0.200 \text{ M} \times 0.0200 \text{ L}.
4. Determine the volume of 0.100 M HI needed to react with the moles of KOH: \text{Volume} = \frac{\text{moles of KOH}}{0.100 \text{ M}}.
5. Determine the volume of 0.100 M HI needed to react with the moles of CH_3NH_2: \text{Volume} = \frac{\text{moles of CH_3NH_2}}{0.100 \text{ M}}.

Key Concepts

Titration

Titration is a quantitative analytical technique used to determine the concentration of a solute in a solution. It involves the gradual addition of a titrant (a solution of known concentration) to a sample until a reaction reaches its equivalence point, where the amount of titrant equals the amount of substance in the sample. Understanding the stoichiometry of the reaction is crucial for calculating the volume of titrant needed.

Equivalence Point

The equivalence point in a titration is the stage at which the amount of titrant added is stoichiometrically equivalent to the amount of substance present in the sample. At this point, the reaction between the titrant and the analyte is complete, and it is often indicated by a color change in the solution if an indicator is used. Knowing the concentrations and volumes of the reactants allows for the calculation of the volume of titrant required to reach this point.

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows chemists to predict the amounts of substances consumed and produced in a reaction. In the context of titration, stoichiometry is essential for determining the volume of acid needed to neutralize a base, as it relates the molarity and volume of the solutions involved.