Determine whether or not the mixing of each pair of solutions results in a buffer. e. 105.0 mL of 0.15 M CH₃NH₂; 95.0 mL of 0.10 M HCl

Verified step by step guidance

1. Identify the components involved in the solution: CH₃NH₂ is a weak base and HCl is a strong acid.
2. Calculate the moles of CH₃NH₂ using the formula: moles = concentration (M) × volume (L).
3. Calculate the moles of HCl using the formula: moles = concentration (M) × volume (L).
4. Determine if the moles of HCl are less than, equal to, or greater than the moles of CH₃NH₂ to see if there is an excess of weak base or if the strong acid completely neutralizes the weak base.
5. Conclude whether a buffer is formed: A buffer is formed if there is a significant amount of weak base and its conjugate acid (formed from the reaction with the strong acid) present in the solution.

Key Concepts

Buffer Solutions

A buffer solution is a system that resists changes in pH upon the addition of small amounts of acid or base. It typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid. Buffers are crucial in maintaining stable pH levels in various chemical and biological processes.

Weak Bases and Their Conjugate Acids

In this scenario, CH3NH2 (methylamine) is a weak base, and when it reacts with HCl (a strong acid), it forms its conjugate acid, CH3NH3+. The presence of both the weak base and its conjugate acid is essential for the formation of a buffer solution, allowing the system to neutralize added acids or bases.

Stoichiometry of Acid-Base Reactions

Stoichiometry involves the calculation of reactants and products in chemical reactions. In this case, determining whether a buffer forms requires calculating the moles of CH3NH2 and HCl to see if they can coexist in a ratio that maintains the buffer capacity. Understanding the stoichiometric relationships helps predict the outcome of mixing these solutions.