PTHH: \(NaOH+HCl\rightarrow NaCl+H_2O\)
Ta có: \(n_{NaOH}=0,3\cdot0,1=0,03\left(mol\right)=n_{HCl\left(p/ứ\right)}\)
+) Trường hợp 1: NaOH còn dư
PTHH: \(Al+NaOH+H_2O\rightarrow NaAlO_2+\dfrac{3}{2}H_2\uparrow\)
Ta có: \(n_{NaOH\left(dư\right)}=n_{Al}=\dfrac{0,27}{27}=0,01\left(mol\right)\)
\(\Rightarrow n_{HCl}=n_{NaOH\left(p/ứ\right)}=0,02\left(mol\right)\) \(\Rightarrow a=C_{M_{HCl}}=\dfrac{0,02}{0,2}=0,1\left(M\right)\)
+) Trường hợp 2: HCl còn dư
PTHH: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
Ta có: \(n_{Al}=0,01\left(mol\right)\) \(\Rightarrow n_{HCl\left(dư\right)}=0,03\left(mol\right)\)
\(\Rightarrow n_{HCl}=0,06\left(mol\right)\) \(\Rightarrow a=C_{M_{HCl}}=\dfrac{0,06}{0,2}=0,3\left(M\right)\)