A student titrates 0.139 g of an unknown monoprotic weak acid to the equivalence point with 44.6 ml of 0.100 m naoh (aq). what is the molar mass of the weak acid?

Respuesta :

The  molar  mass  of  the  weak   acid  is  calculated  as  follows

by use of  an  example  of  monoprotic  weak  such  as CH3COOH   reacting  with  NaOH

that  is NaOH + CH3COOH  = CH3COONa + H2O

calculate  the moles  of NaOH  used
=  molarity  x  volume/1000

= 44.6  ml  x  0.100/ 1000  = 4.46  x10^-3  moles

by  use of mole  ratio  between NaOH  to monoprotic  acid which  is1:1  the moles  of   monoprotic  acid  is  also  4.46  x10^-3 moles

molar  mass  is therefore = mass/  moles = 0.139 g/ (4.46 x10^-3) =  31.17 g/mol