Which of the following combinations will make a good buffer solution?
0.05 M H2CO3 + 0.05 M KHCO3
0.5 M HI + 0.5 M CsI
0.3 M NH4Cl
0.3 M NH4Cl + 0.1 M NH3
0.3 M NH4Cl + 0.1 M HCl
thanks
You KNOW #1 and #3 are buffers.
To identify which combination will make a good buffer solution, we need to consider a buffer solution's requirements. A buffer solution consists of a weak acid and its conjugate base or a weak base and its conjugate acid. It is responsible for resisting changes in pH when small amounts of acid or base are added.
Now, let's analyze each combination:
1. 0.05 M H2CO3 + 0.05 M KHCO3:
This combination involves carbonic acid (H2CO3) and potassium bicarbonate (KHCO3). H2CO3 is a weak acid, and KHCO3 is its conjugate base. Therefore, this combination can make a good buffer solution.
2. 0.5 M HI + 0.5 M CsI:
The combination of hydroiodic acid (HI) and cesium iodide (CsI) does not involve a weak acid and its conjugate base or a weak base and its conjugate acid. Therefore, this combination will not make a good buffer solution.
3. 0.3 M NH4Cl:
This only contains ammonium chloride (NH4Cl), which is a salt. It does not have a weak acid or base component. Therefore, this combination alone will not make a good buffer solution.
4. 0.3 M NH4Cl + 0.1 M NH3:
This combination involves ammonium chloride (NH4Cl) and ammonia (NH3). NH4Cl is a salt, and NH3 is a weak base and the conjugate base of NH4Cl. Therefore, this combination can make a good buffer solution.
5. 0.3 M NH4Cl + 0.1 M HCl:
This combination also involves ammonium chloride (NH4Cl), but instead of a weak base, it includes hydrochloric acid (HCl), which is a strong acid. Since a buffer solution requires a weak acid and its conjugate base or a weak base and its conjugate acid, this combination will not make a good buffer solution.
Therefore, the combinations that will make good buffer solutions are:
- 0.05 M H2CO3 + 0.05 M KHCO3
- 0.3 M NH4Cl + 0.1 M NH3
A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added to it. To be a good buffer solution, it should consist of a weak acid and its conjugate base or a weak base and its conjugate acid.
From the given options, the combination of 0.05 M H2CO3 (weak acid) + 0.05 M KHCO3 (conjugate base) will make a good buffer solution. It consists of a weak acid and its conjugate base.
The other options do not have a clear combination of a weak acid and its conjugate base or a weak base and its conjugate acid, hence they will not form a good buffer solution.