A sample of `H_(2) SO_(4)` (density `1.787 g mL^(-1)`) si labelled as 86% by weight. What is the molarity of acid? What volume of acid has to be used to make `1 L` of `0.2 M H_(2) SO_(4)` ?

Explanation

` :. 100 " g of " H_(2)SO_(4)` solution contains 86 g of `H_(2)SO_(4)`
` :. 100/(1.787)" mL " H_(2)SO_(4)` solution contains `86/98` mole .
` :. 100 mL H_(2)SO_(4) ` solution contains `86/98 xx (1.787)/(100) xx1000`
` = 15.68 M `
` :. " normality of "H_(2)SO_(4) = (2xx 15.68) N = 31.68 N `
( basicity of `H_(2)SO_(4)=2`)
Suppose that v mL of `31.36 " N " H_(2)SO_(4)` is to used to make 100 mL of` 0.2 M" (i.e ., 0.4 N )" H_(2)SO_(4)`
` :. ` m.e of v mL of `31.36 " N " H_(2)SO_(4) =` m.e of 1000 mL of `0.4 " N " H_(2)SO_(4)`
`31.36 xx v = 0.4 xx1000`
` v = (0.4 xx1000)/(31.36) = 12.75 mL `