A student completes titration by adding 12.0 mL of NaOH(aq) of an unknown concentration to 16.0 mL of 0.15M HCl(aq). what is the molar concentration of the NaOH(aq)?
The easy way to do this is
mL NaOH x M NaOH = mL HCl x M HCl
This equation works only when the reactants are 1:1 in the equation as is the case with HCl and NaOH.
NaOH + HCl ==> NaCl + H2O
0.11M
Using the formula:
mL NaOH x M NaOH = mL HCl x M HCl
We can plug in the values and solve for M NaOH:
12.0 mL x M NaOH = 16.0 mL x 0.15 M
M NaOH = (16.0 mL x 0.15 M) / 12.0 mL
M NaOH = 0.20 M / 12.0 mL
M NaOH = 0.0167 M
Therefore, the molar concentration of the NaOH(aq) is 0.0167 M (or approximately 0.02 M).
To find the molar concentration of NaOH(aq), we can use the concept of stoichiometry. In a titration, a reaction takes place between the known concentration of one substance (HCl in this case) and the unknown concentration of the other substance (NaOH in this case). The balanced equation for the reaction between NaOH and HCl is:
NaOH + HCl -> NaCl + H2O
From this equation, we can see that the stoichiometric ratio between NaOH and HCl is 1:1, which means that for every 1 mole of NaOH, we need 1 mole of HCl.
Given the volume and concentration of HCl, we can calculate the number of moles of HCl using the formula:
moles of HCl = volume of HCl (in L) x molarity of HCl
Converting the given volume of HCl from mL to L:
volume of HCl = 16.0 mL = 16.0 mL / 1000 mL/L = 0.016 L
Now we can calculate the moles of HCl:
moles of HCl = 0.016 L x 0.15 M = 0.0024 moles
Since the stoichiometric ratio between NaOH and HCl is 1:1, the number of moles of NaOH is also 0.0024 moles.
Next, we need to find the molar concentration of NaOH. To do this, we need the volume of NaOH used in the titration. From the given information, the volume of NaOH used is 12.0 mL.
Calculating the volume of NaOH in liters:
volume of NaOH = 12.0 mL = 12.0 mL / 1000 mL/L = 0.012 L
Finally, we can find the molar concentration of NaOH:
molarity of NaOH = moles of NaOH / volume of NaOH
molarity of NaOH = 0.0024 moles / 0.012 L = 0.20 M
Therefore, the molar concentration of NaOH(aq) is 0.20 M.