Which solution has the highest pH?
1. 0.1 M C6H5NH3Cl,
Kb C6H5NH2 = 4.2 × 10−10
2. 0.1 M NH2(OH)2Cl,
Kb NH2OH = 6.6 × 10−9
3. 0.1 M NaCl, Kb � zero
4. 0.1 M NH4Cl, Kb NH3 = 1.8 × 10−5
5. 0.1 M CH3NH3Cl,
Kb CH3NH2 = 5.0 × 10−4
how the hell are you supposed to work it out. that's what we need to know
^rt
DrBob222 please answer only if you have a legitimate answer and explanation. This doesn't help me at all.
The answer is 0.1 M NaCl, Kb of about zero.
Kb is the amount of base and if there is no base (which translates to pOH=0) then it is extremely acidic (the pH=14).
I hope the explanation makes sense, but the answer is correct.
To determine which solution has the highest pH, we need to compare the strength of the bases in each solution. The stronger the base, the higher the pH will be.
To compare the strength of bases, we can use the value of Kb (base ionization constant). Higher values of Kb indicate stronger bases.
Let's analyze each solution:
1. 0.1 M C6H5NH3Cl:
- Base: C6H5NH2
- Kb (base ionization constant) = 4.2 × 10^−10 (small value)
- The base is weak.
2. 0.1 M NH2(OH)2Cl:
- Base: NH2OH
- Kb = 6.6 × 10^−9 (small value)
- The base is weak.
3. 0.1 M NaCl:
- NaCl is a salt and does not contain any basic component that can contribute to the pH of the solution.
- Kb = zero (not applicable).
4. 0.1 M NH4Cl:
- Base: NH3
- Kb = 1.8 × 10^−5 (larger value compared to the previous two bases)
- The base is relatively stronger.
5. 0.1 M CH3NH3Cl:
- Base: CH3NH2
- Kb = 5.0 × 10^−4 (largest value among all the given bases)
- The base is the strongest.
Comparing the values of Kb, we can conclude that solution 5, 0.1 M CH3NH3Cl, has the highest pH since its base (CH3NH2) has the largest Kb value.