Question

Calculate the molarity of a solution of sodium hydroxide, naoh, if 23.64 ml of this solution is needed to neutralize 0.5632 g of potassium hydrogen phthalate, khc8h4o4.

Answer 1

the molarity of NaOH needed is calculated as follows
calculate the moles of KhC8h4O4

that is moles = mass/molar mass of KhC8h4O4(204.22 g/mol)

=0.5632g /204.22g/mol= 2.76 x10^-3 moles

write the equation for reaction

khc8h4O4 + NaOH ---> KNaC8h4O4 + H2O

from the equation above the reacting ratio of KhC8h4O4 to NaOh is 1:1 therefore the moles of Naoh is also 2.76 x10^-3 moles

molarity of NaOh = (moles of NaOh / volume ) x 1000

that is { (2.76 x10^-3) / 23.64} x100 =0.117 M