Răspuns :
ms =5 +2 + 1 =8kg
md (NaOH)=5 *20/100 +2*60/100=2,2kg
c final = 2,2*100/8=27,5%
Stim ca c% = mdx100/ms
c1% = 20/100 = 20%
ms1 = 5 kg
=> md1 = 5x20/100 = 1 kg
c2% = 60/100 = 60%
ms2 = 2 kg
=> md2 = 2x60/100 = 1,2 kg
m.apa = 1 kg
=> md.tot = md1 + md2 = 1 + 1,2 = 2,2 kg
=> ms.tot = ms1 + ms2 + m.apa = 5 + 2 + 1 = 8 kg
=> c%.final = md.tot x 100 / ms.tot.
=> c%.final = 2,2x100/8 = 27,5%