A bottle of commercial sulphuric acid (density = 1.787 g `mL^(-1))` is labelled as 86 per cent by mass
What is the molarity of the acid ?
What volume of the acid has to be used to make 1 liotre of 0.2 M `H_(2)SO_(4)` ?

Answer

15.7 M
12.7 mL

Explanation

Step I. Calculation of molarity of the acid solution.
`"Mass of solution"=100 g, "Density of solution "=1.787"gm L"^(-1)`
`"Volume of 100 g of solution"=("Mass")/("Density")=((100g))/((1.787" gm L"^(-1)))=55.9mL=0.0559 L.`
`"Molarity of solution (M)"= ("Mass of" H_(2)SO_(4)//"Molar mass")/("Volume of solution in Litres")=((86g)//(98"g mol"^(-1)))/((0.0559L))`
`=15.7" mol L"^(-1)=15.7 M.`
Step II. `"Volume of "H_(2)SO_(4)"required".`
`"Applying molarity equation," M_(1)V_(1)=M_(2)V_(2)`
`(15.7 M)xxV_(1)=(0.2 M)xx(1L)`
`V_(1)=((0.2M)xx(1L))/((15.7M))=0.0127xx1000=12.7 mL.`