Respuesta :
Answer:
The pH of the resulting solution is 12.9.
Explanation:
Molarity of the HCl solution = 0.20 M
Volume of the HCl solution = 36.0 mL
[tex]1 mL = 0.001 L\\36.0 mL=36.0\times 0.001 L=0.0360 L[/tex]
Moles of HCl = n
[tex]0.20 M=\frac{n}{0.0360 L}\\n=0.20 M\times 0.0360 L=0.0072 mol[/tex]
Molarity of NaOH solution = 0.40 M
Volume of the NaOH solution = 30.0 mL
[tex]1 mL = 0.001 L\\30.0 mL=30.0\times 0.001 L=0.0300 L[/tex]
Moles of NaOH = n'
[tex]0.40 M=\frac{n'}{0.0300 L}\\n'=0.40 M\times 0.0300 L=0.012 mol[/tex]
[tex]HCl(aq)+NaOH(aq)\rightarrow NaCl(aq)+H_2O(l)[/tex]
According to the reaction, 1 mole of HCl reacts with 1 mole of NaOH then 0.0072 moles of HCl will react with :
[tex]=\frac{1}{1}\times 0.0072 mol=0.0072\text{ mol of NaOH}[/tex]
Mole of NaOH remained unreacted = 0.012 mol - 0.0072 mol = 0.048 mol
[tex]NaOH (aq)\rightarrow Na^+(aq)+OH^-(aq)[/tex]
Moles of Hydroxide ions remained unreacted = 0.0048 mol
These unreacted moles of hydroxide ion will be responsible for the pH of the final solution
Moles of hydroxide ions remained unreacted = 0.048 mol
Volume of the final solution = 36.0 mL + 30.0 mL = 66.0 mL
[tex]1 mL = 0.001 L\\66.0 mL=66.0\times 0.001 L=0.0660 L[/tex]
Molarity of the remained hydroxide ions in final solution:
[tex][OH^-]=\frac{0.0048 mol}{0.0660 L}=0.073 M[/tex]
The pOH of the final solution :
[tex]pOH=-\log[OH^-]\\pOH=-\log[0.073 M]=1.1\\14 = pH + pOH\\pH = 14 - pOH = 14 - 1.1 = 12.9[/tex]
The pH of the resulting solution is 12.9.
Answer:
pH = 1.14
Explanation:
[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]
From the above balanced reaction we observe that molar ratio for NaOH and HCl is equal.
Therefore at an equivalent point where the complete neutralization will occur, their respective concentrations are:
HCl being a strong acid:
[tex][H^+]=[HCl][/tex]
NaOH being a strong base:
[tex][OH^-]=[NaOH][/tex]
gram equivalent of HCl = 0.2 × 36 /1000 = 7.2/1000
gram equivalent of NaOH = 0.4 × 30 /1000 = 12/1000
gram equivalent of HCl remains after mixing = 4.8 /1000
Volume of mixture = 36 + 30 = 66 mL = 66/1000 litre
Normality of HCl in mixture = 4.8/1000 ÷ 66/1000 = 0.073
ion concentration = 0.073
pH = - log 0.073
pH = 1.14
