54 mL Ba(OH)2x(0.101 mol Ba(OH)2/1000 mL) x (2 mol OH-/ 1 mol Ba(OH)2 ) = 0.0109 mol OH-
0.0109 mol OH-x (1mol HCl/ 1 mol OH- ) = 0.0109 mol HCl
0.109 mol HCl/(0.130 mol/L HCl) = 0.0839 L HCl
0.0839 L HCl * 1000mL = 83.9 mL of 0.130 M HCl
The answer is "filtration"
Filtration is used to seprate a solid from a liquid in which it is suspended. Filtration is also used to separate a substance from a mixture because one is insoluble in the solvent and the other is solube. The separation is due to particle size.
I hope this helps.
Convert mole to gram by multiplying the molar mass of sodium
0.500mol Na x 22.990g = 11.495g of Na
