In standardization, 8.77 mL of NaOHNaOH neutralized 1.522 g of KHPKHP. Given the molar mass of KHPKHP is 204.22 g/mol, what is the molarity of the NaOHNaOH solution?

1 Answer
Jun 13, 2017

"Molarity"=0.8500*mol*L^-1Molarity=0.8500molL1

Explanation:

KHPKHP, "potassium hydrogen phthalate"potassium hydrogen phthalate, 1,2-C_6H_4CO_2HCO_2^(-)K^(+)1,2C6H4CO2HCO2K+, is the potassium salt of the diacid, "pthalic acid"pthalic acid, 1,2-C_6H_4(CO_2H)_21,2C6H4(CO2H)2.

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It can be titrated as a base, or here as an acid. It is air stable, non-hygroscopic, and thus useful as a primary standard.

1,2-C_6H_4CO_2HCO_2^(-)K^(+)+Na^(+)""^(-)OH rarr "1,2-"C_6H_4CO_2^(-)Na^(+)CO_2^(-)K^(+)+H_2O1,2C6H4CO2HCO2K++Na+OH1,2-C6H4CO2Na+CO2K++H2O

And thus moles of NaOHNaOH -= "KHP"KHP, and thus............

[NaOH]=((1.522*g)/(204.22*g*mol^-1))/(8.77xx10^3*L)=0.8500*mol*L^-1[NaOH]=1.522g204.22gmol18.77×103L=0.8500molL1.