a)
Al + 4HNO3 -----> 2H2O + NO + Al(NO3)3x------------------------------------x
Fe + 4HNO3 ----->2H2O + NO + Fe(NO3)3y------------------------------------2y
n NO=\(\frac{6,72}{22,4}=0,3\left(mol\right)\)
Theo bài ra ta có pt
\(\left\{{}\begin{matrix}27x+56y=11\\x+y=0,3\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
m Al=0,2.27=5,4(g)
m Fe =0,1.56=5,6(g)
b) Theo pthh
n muối =n khí=0,3(mol)
m muối =0,3(213+242)=136,5(g)