6.D
7.\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(\Rightarrow2+3+1+3=9\)
Chọn A.
8.\(n_{NaOH}=0,2\cdot2=0,4mol\)
Để trung hòa: \(n_{H^+}=n_{OH^-}=0,4mol\)
\(\Rightarrow n_{H_2SO_4}=0,2mol\Rightarrow V=\dfrac{0,2}{2}=0,1l=100ml\)
Chọn D.
9.C
10.D
11.C
12.\(n_{Al}=\dfrac{5,4}{27}=0,2mol\)
\(BTe:3n_{Al}=2n_{SO_2}\Rightarrow n_{SO_2}=0,3mol\)
\(\Rightarrow V=6,72l\)
Chọn B