Question

x g solutie NaOH 30% se amesteca cu y g solutie NaOH 35%, obtinandu-se o solutie de concentratie 32%. Prin solutia obtinuta se barboteaza 4 l clor la t = 273 grade C si p = 5,6 atm, obtinandu-se apa de Javel. Excesul de NaOH se neutralizeaza cu 630 g solutie HNO3 30%. Determina x si y.

Answer 1

Intai aplicam formula: ms1/ms2=(c2-cf)/(cf-c1) => x/y=(35-32)/(32-30) => x/y=3/2 => x=3y/2=1,5y
pV=nRT => n=pV/RT => n=5,6*4/(0,082*2*273)=0,5moli Cl2
6*40g......3moli
6NaOH + 3Cl2 -> 5NaCl + NaClO3 + H2O
a=40g......0,5moli
md=c*ms/100=30*630/100=189g HNO3
40g.........63g
NaOH + HNO3 -> NaNO3 + H2O
b=120g..189g
mdf=160g => msf=(x+y)=160*100/32=500g
stim ca x+y=500 si x=1,5y
1,5y+y=500 => 2,5y=500 => y=200g solutie NaOH 35%
x=300g solutie NaOH 30%