Question

150 mL of C2 H5 OH (density = 0.78g mL–1) is diluted to one litre by adding water ; molarity of the solution is

Answer 1

density= mass/volume

:. mass= density×volume

:.m= 0.78 × 150

:. m= 117 g

Mol. wt. of C2H5OH= 46 g/mol

:. moles(n) of C2H5OH = 117/46= 2.543 mol

Volume of solution= 1 L

Molarity= no. of moles of solute/ volume of solution in litres

:.M= 2.543/1 = 2.543 M

:. Molarity of 1L C2H5OH is 2.543 M.