`100cm^(3)` of an aqueous solution of `BaCIU_(2)2H_(2)O` is found to contain `6.022xx10^(22)CI^(-1)`ilos. Calculate the molarity of the solution.

Answer

0.5 M

Explanation

Step I. Calculation of mass of `BaCI_(2)2H_(2)O` in the solution.
Barium chloride is a strong electrolyte. It is completely ionised in solution. The number of different species in the solution may be represented as :
`BaCI_(2)2H_(2)O(s)overset(("aq"))toBa^(2+)("aq")+ 2CI^(-)("aq")+aH_(2)O`
`(3.011xx10^(22)"molecules")" "(3.011xx10^(22))" "(6.022xx10^(22))`
`"Gram molecular mass of "BaCI_(2)2H_(2)O=137.5+2xx35.5+2xx18=244" g mol"^(-1)`
`6.022xx10^(23)" molecules of "BaCI_(2).2H_(2)O" correspond to mass"=244.5 g.`
`6.022xx10^(23)" molecules of "BaCI_(2).2H_(2)O" correspond to mass"=((3.011xx10^(22)))/((6.022xx10^(23)))xx244.5 g=12.225 g.`
Step II. Calculation of molarity of the solution.
`"Molarity of soltuion (M)"=("Mass of "BaCI_(2).2H_(2)O"/Molar mass")/("Volume of solution in Litres")=((12.225g)//(244.5"g mol"^(-1)))/((0.1 L))`
`o.5 "mol L"^(-1)=0.5 M.`