1.

xg of NaCl (M=58.5) put in a dry flask and water was added with continous strring to produce exactly 1L solution having a molality of 2.00. Find x using the data below: ltbr. Weight % NaCl Weight % NaCl 0 10 12 14 ltbr. Density of solution in g//mL 1.0591 1.0742 1.0895 1.1049

Answer»


Solution :Molality `=("WT of solute//molar mass of solute")/(("wt of solvent in "GM)/(1000))`
`2=((x)/(58.5))/((W)/(1000))`
or `(x)/(W)=(2xx58.5)/(1000)=0.117`
Now we find `%` wt. of `NaCl`
i.e. `(x)/(x+W)xx100=10.4`
So with the help of table GIVEN.
Density of solution in `gm//mL=1.0742`
Now for `1` it solution
wt of solution `=1074.2gm`
`therefore` wt of solution `=(1074.2-X)gm=W`
`because (x)/(W)=0.117` or `(x)/(1074.2-x)=0.117`
`therefore x=112.5 gram`.


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