ro = p = ms/Vs => ms = pxVs = 2x1000x1,29 = 2580 g sol. H2SO4
c% = mdx100/ms => md1 = ms1xc1/100 = 2580x38/100
= 980,4 g H2SO4
c2 = 20% , a = masa de acid consumata si vom avea:
md2 = md1-a
ms2 = ms1-a
=> 20 = (980,4-a)100/(2580-a)
=> 2580-a = 5(980,4-a)
=> a = 580,5 g H2SO4 consumata