a, PTHH: \(2K+Cl_2\rightarrow2KCl\)
b, \(n_{Cl_2}=\dfrac{1}{2}n_{KCl}=\dfrac{1}{2}n_K=\dfrac{1}{2}.\dfrac{3,9}{39}=0,05\left(mol\right)\)
\(\Rightarrow V_{Cl_2}=0,05.22,4=1,12\left(l\right)\left(đktc\right)\)
c, \(n_{KCl}=n_K=0,1\left(mol\right)\)
\(\Rightarrow M_{KCl}=74,5.0,1=7,45\left(g\right)\)