nNaOH=20.10%:40=0,05 mol
2NaOH+H2SO4=Na2SO4+2H2O
=> nH2SO4=0,025 mol
=> V H2SO4=0,025/2=0,0125l=12,5 ml
Mặt khác:
2NaOH+MgCl2=Mg(OH)2+2NaCl
nNaOH=0,05 mol => nMg(OH)2=0,025 mol
=> mMg(OH)2=0,025.58=1,45g
2NaOH+H2SO4-->Na2SO4+2H2O
m NaOH=\(\frac{20.10}{100}=2\left(g\right)\)
n NaOH=\(\frac{2}{98}=0,02\left(mol\right)\)
Theo pthh
n H2SO4=1/2n NaOH=0,01(mol)
VH2SO4=\(\frac{0,01}{2}=0,005\left(mol\right)\)
2NaOH+MgCl2--->Mg(OH)2+2NaCl
Theo pthh
n Mg(OH)2=1/2 n NaOH=0,01(mol)
m Mg(OH)2=0,01.58=0,58(g)