Please explain

Question

How many millilitres of concentrated h2so4 of density 1.84 g/mL containing 98% h2so4 by mass are required to make (a) 1 litre of 0.5 M solution (b) 4 litres of 1N solution and (c) 200 mL of 0.25 M solution?

Answer 1

molecular weight of sulfuric acid = 98g 

Specic Gravity  = 1.84 

% of pure sulphuric acid/gm = 98% 

number of replacable hydrogens = 2 

Gram Equivalent Weight =molecular weight/replaceable hydrogens 98/2 = 49g 

Required substance weight = eq. wt. x Normality x Volume (in L) =49gm x0.5N X 0.2 Litres = 4.9 g  

Dilution Factor = Specic Gravity x concentration of pure acid. =1.84 x 0.98 = 1.8gm 

Volume required = mass required/dilution factor  4.9/1.8 = 2.72ml.