solutia de NaOH :ms = 200g c = 20% ⇒ md = 40g nNaOH = 40/40 = 1mol
solutia de H2SO4 : ms = 200g c = 49% ⇒ md = 98g n acid = 1mol
reactioneaza : 1mol NaOH + 0,5 moli H2SO4
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substanta in exces : H2SO4 - 0,5moli ms exces = 49·100/49 = 100g