Respuesta :
Answer: The molar mass of acid is 127.97 g/mol
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}[/tex]
Molarity of NaOH solution = 0.270 M
Volume of solution = 36.4 mL
Putting values in above equation, we get:
[tex]0.270M=\frac{\text{Moles of NaOH}\times 1000}{36.4}\\\\\text{Moles of NaOH}=\frac{0.270\times 36.4}{1000}=0.00983mol[/tex]
The chemical equation for the reaction of NaOH and diprotic acid follows:
[tex]2NaOH+H_2X\rightarrow 2NaX+2H_2O[/tex]
By Stoichiometry of the reaction:
2 moles of NaOH reacts with 1 mole of diprotic acid
So, moles of diprotic acid = [tex]\frac{0.00983}{2}=0.004915moles[/tex]
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Mass of acid = 0.629 g
Moles of acid = 0.004915 moles
Putting values in above equation, we get:
[tex]0.004915mol=\frac{0.629g}{\text{Molar mass of acid}}\\\\\text{Molar mass of acid}=\frac{0.629g}{0.004915mol}=127.97g/mol[/tex]
Hence, the molar mass of acid is 127.97 g/mol
