2Na+2H2O---->2NaOH+H2
0,2------------------0,2-------0,1
n\(_{Na}=\frac{4,6}{23}=0,2\left(mol\right)\)
V\(_{H2}=0,1.22,4=2,24\left(l\right)\)
m\(_{H2}=0,2\left(g\right)\)
C%=\(\frac{0,2.40}{200+4,6-0,2}.100\%=3,91\%\)
nNa= 4,6/23= 0,2(mol)
PTHH: 2Na+ 2H2O ____> 2NaOH+ H2
p/ứ: 0,2................................. 0,2........ 0,2 (mol)
VB=VH2= 0,2 x 22,4= 4,48 (lít)
C%dd NaOH = \(\frac{0,2\cdot39}{4,6+200}\cdot100\%\approx3,81\%\)