contestada

During a titration a student found that 20.0cm3 of sodium carbonate solution
neutralised 27.9 cm3 of 0.500 mol/dm3 nitric acid solution.
Calculate the concentration of the sodium carbonate solution in mol/dm3. Give
your answer to 3 significant figures.


Respuesta :

Answer: The concentration of [tex]Na_2CO_3[/tex] required is [tex]0.349mol/dm^3[/tex]

Explanation:

According to the neutralization law,

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1[/tex] = basicity of [tex]HNO_3[/tex] = 1

[tex]M_1[/tex] = molarity of [tex]HNO_3[/tex] solution = [tex]0.500 mol/dm^3[/tex]

[tex]V_1[/tex] = volume of  [tex]HNO_3[/tex] solution = [tex]27.9cm^3[/tex]

[tex]n_2[/tex] = acidity of [tex]Na_2CO_3[/tex] = 2

[tex]M_1[/tex] = molarity of [tex]Na_2CO_3[/tex] solution =?

[tex]V_1[/tex] = volume of  [tex]Na_2CO_3[/tex] solution =  [tex]20.0cm^3[/tex]  

Putting in the values we get:

[tex]1\times 0.500\times 27.9=2\times M_2\times 20.0[/tex]

[tex]M_2=0.349mol/dm^3[/tex]

Therefore, concentration of [tex]Na_2CO_3[/tex] required is [tex]0.349mol/dm^3[/tex]