a)\(Na2SO4+BaCl2--.>BaSO4+2NaCl\)
\(m_{Na2SO4}=\frac{17,75.8}{100}=1,42\left(g\right)\)
\(n_{Na2SO4}=\frac{1,42}{142}=0,01\left(mol\right)\)
\(n_{BaCl2}=\frac{31,2.10}{100}=3,12\left(g\right)\)
\(n_{BaCl2}=\frac{3,12}{208}=0,015\left(mol\right)\)
=> BaCl2 dư
dd sau pư là BaCl2 dư và NaCl
\(n_{BaCl2}dư=0,05\left(mol\right)\)
\(m_{BaCl2}=0,005.208=1,04\left(g\right)\)
\(m_{ddBaCl2}dư=\frac{1,04.100}{10}=10,4\left(g\right)\)
\(d_{BaCl2}=\frac{10,4}{40}=0,26\left(\frac{g}{ml}\right)\)
b) \(C_{M\left(BaCk2\right)}=\frac{0,005}{0,04}=0,125\left(M\right)\)
\(n_{NaCl}=2n_{Na2SO4}=0,02\left(mol\right)\)
\(C_{M\left(NaCl\right)}=\frac{0,02}{0,04}=0,5\left(M\right)\)
