1.

What volume of 98% sulphuric acid should be mixed with water to obtain 200mL of 15% solution of sulphuric acid by weight ? Given density of H_(2)O=1.00 g cm^(-3), sulphuric acid (98%)=1.88g cm^(-3) and sulphuric acied (15%)=1.12g cm^(-3).

Answer»


Solution :It is a CASE of DILUTION, simplest way is to determine normally of the `98%` and `15% H_(2)SO_(4)`.
(i) For `98% H_(2)SO_(4) : 100g H_(2)SO_(4)` solution `=(100)/(1.88)cm^(3)` solution has `H_(2)SO_(4)=98g`
`N_(1)(98%)=(1000w_(1))/(E_(1)V)=(100xx98)/(49xx(100)/(1.88))=37.6N`
where `w_(1)` is the WEIGHT of solute of EQUIVALENT weight `E,` in `V mL` solution
(ii) For `15% H_(2)SO_(4) : 100g H_(2)SO_(4)` solution `=(100)/(1.12)cm^(3)` has `H_(2)SO_(4)=15g`
`N_(2)(15%)=(1000w_(1))/(E_(1)V)=(1000xx15)/(49xx(100)/(1.12))=3.43`
Using `N_(1)V_(1)=N_(2)V_(2)`
`37.6xxV_(1)=3.43xx200`
`V_(1)=18.2 mL`


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