ta có : \(\dfrac{Mg\left(OH\right)_2}{x}\dfrac{+}{ }\dfrac{2HCl}{2x}\dfrac{\rightarrow}{ }\dfrac{MgCl_2}{x}\dfrac{+}{ }\dfrac{2H_2O}{ }\)
\(\dfrac{Cu\left(OH\right)_2}{y}\dfrac{+}{ }\dfrac{2HCl}{2y}\dfrac{\rightarrow}{ }\dfrac{CuCl_2}{y}\dfrac{+}{ }\dfrac{2H_2O}{ }\)
\(\dfrac{NaOH}{z}\dfrac{+}{ }\dfrac{HCl}{z}\dfrac{\rightarrow}{ }\dfrac{NaCl}{z}\dfrac{+}{ }\dfrac{H_2O}{ }\)
ta có : khối lượng của muối là 24,1g
\(\Rightarrow95x+135y+58,5z=24,1\left(1\right)\)
ta có : \(n_{HCl}=0,4\left(mol\right)\)
\(\Rightarrow2x+2y+z=0,4\left(2\right)\)
từ \(\left(1\right)\) và \(\left(2\right)\) \(\Rightarrow\)ta có : \(m=58x+98y+40z=95x+135y+58,5-18,5\left(2x+2y+z\right)\)
\(=24,1-18,5\left(0,4\right)=16,7\left(g\right)\)
vậy \(m=16,7\left(g\right)\)