Answer:
Option b will not have enough base to completely neutralize the sample of H2SO4. [It only has 1/2 the amount needed].
Step-by-step explanation:
Note: The abbreviation for molar is M, not m.
Which one of the following basic solutions will not neutralize 25.0 ml of a 1.0M sulfuric acid solution?
a. 100.0 ml of 0.50M NaOH
b. 25.0 ml of 1.0M NaOH
c. 50.0 ml of 1.0M NaOH
d. 25.0 ml of 2.0M KOH
e. all of these will neutralize 25.0 ml of a 1.0M sulfuric acid solution.
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The first thing needed is a balanced equation for the neutralization reaction:
2NaOH + H2SO4 = Na2SO4 + H2O for the NaOH options
and 2KOH + H2SO4 = K2SO4 + H2O for the KOH option.
Its a good thing we checked, since we find that two moles of NaOH or KOH are needed to neutralized every 1 mole of H2SO4 (H2SO4 contributes 2 H ions for each molecule of H2SO4).
The next step is to determine the number of moles present in the 25.0ml of 1 M H2SO4. Moles of a solute can be found by multiplying the volume times the concentration:
Moles = Volume x Concentration
As an example, lets find the moles of H2SO4 in 25.0 ml of 1.0M H2SO4.
moles = (25.0ml)*(1.0M H2SO4)
First, remember that M (molar) stands for moles/liter. Lets use the complete unit in place of M:
moles = (25.0ml)*(1.0 moles/liter H2SO4)
We can see that we need a conversion factor that would allow us to cancel the two volume units: ml and liter). [1 liter/1000 ml)]
moles = (25.0ml)*(1.0 moles/liter H2SO4)*(1 liter/1000 ml)
Liters and ml both cancel:
moles = (25.0)*(1.0 moles H2SO4)*(1/1000)
moles = 0.025 moles H2SO4
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Note that each mole of H2SO4 contains 2 moles of H atoms. So when we consider how much NaOH or KOH is needed to neutralize all the H atoms, we need to double the 0.025 moles of H2SO4 since that will be the moles of H ions that are in the solution: 0.050 moles H ions.
To determine which of the options provide enough
Now we know that we need 0.050 moles of NaOH or KOH. The next step is to determine the moles of either NaOH or KOH that are present in each of the options.
Use the same process as described above to calculate the moles of KNaOH or KOH in the options. moles = (volume)*(concentration)
Make sure the units are correctly cancelled.
The result is:
(moles/liter)
Vol.(ml) Vol (L) Conc.(M) moles H^+
a. 100 0.1 0.5 0.05
b. 25 0.025 1 0.025
c. 50 0.05 1 0.05
d. 25 0.025 2 0.05
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H2SO4 25 0.025 1 0.025 0.05
Option a, c and d all provide the moles of base required to neutralize the 0.05 moles of hydrogen ions.