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-A sample consist 90% NaOH and 10% CaO,whats the concentration of NaOH in the solution of this 3g sample,dissolved in 250cm3.

-How many cm3 of H2SO4 with concentration of 0.255M are needed for titration of 100cm3 of this solution

1 answer

amount NaOH = 3*0.9 = 2.7g
amount CaO = 3*0.10 = 0.3 g

mols NaOH = 2.7g/molar mass NaOH.
mols CaO = 0.3 g/molar mass CaO.

M NaOH = mols NaOH/0.250L
M CaO = mols CaO/0.250L

For the titration.
mols CaO = M x L = ?
mols NaOH = M x L = ?

Set up equations for the titration with H2SO4, solve for cc H2SO4 for NaOH and cc H2SO4 for CaO, then add cc H2SO4 to total. Post your work if you get stuck.