\(V_{\text{dd}}=0,2+0,3=0,5\left(l\right)\\ n_{HCl}=0,2.1+0,3.0,5=0,35\\ C_M=\dfrac{0,35}{0,5}=0,7M\)

200ml = 0,2(l)

=> nHCl (1) = 0,2 .1 = 0,2 (mol)

300ml = 0,3 (l)

=> nHCl(2) = 0,3 . 0,5 = 0,15 (mol)

=> CM (sau khi trộn) = n/V = (0,15+0,2) / (0,2+0,3 ) = 0,35 / 0,5 = 0,7 M

Đáp án C

C_{M HCl}= (0,2+0,3.2)/0,5= 1,6M

Đáp án C

\(\sum\)n_HCl=0,2.2+0,3.4=1,6(mol)

C_M dd HCl=\(\dfrac{1,6}{0,5}=3,2M\)

Bài 1:

Ta có: \(n_{OH^-}=n_{Na^+}=n_{NaOH}=0,2.0,4=0,08\left(mol\right)\)

\(n_{H^+}=n_{Cl^-}=n_{HCl}=0,4.0,3=0,12\left(mol\right)\)

PT ion: \(OH^-+H^+\rightarrow H_2O\)

_____0,08_____0,12 (mol)

⇒ n_{OH^- (dư)} = 0,04 (mol)

\(\Rightarrow\left\{{}\begin{matrix}\left[Na^+\right]=\frac{0,08}{0,6}\approx0,133M\\\left[Cl^-\right]=\frac{0,12}{0,6}=0,2M\\\left[OH^-\right]=\frac{0,04}{0,6}\approx0,066M\end{matrix}\right.\)

Câu 2:

Ta có: \(\Sigma n_{K^+}=n_{KCl}+2n_{K_2SO_4}=0,2.1,5+0,3.2.2=1,5\left(mol\right)\)

\(n_{Cl^-}=n_{KCl}=0,2.1,5=0,3\left(mol\right)\)

\(n_{SO_4^{2-}}=0,3.2=0,6\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\left[K^+\right]=\frac{1,5}{0,5}=3M\\\left[Cl^-\right]=\frac{0,3}{0,5}=0,6M\\\left[SO_4^{2-}\right]=\frac{0,6}{0,5}=1,2M\end{matrix}\right.\)

Bạn tham khảo nhé!

a) Ta có: \(\left\{{}\begin{matrix}n_{CuCl_2}=0,3\left(mol\right)\\n_{BaCl_2}=0,1\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left[Cu\right]=\dfrac{0,3}{0,5}=0,6\left(M\right)\\ \Rightarrow\left[Ba\right]=\dfrac{0,1}{0,5}=0,2\left(M\right)\\ \Rightarrow\left[Cl\right]=\dfrac{0,3.2+0,1.2}{0,5}=1,6\left(M\right)\)

\(a.300ml=0,3l\\ n_{Ba\left(OH\right)_2}=0,3.0,5=0,15mol\\ Ba\left(OH\right)_2+2HCl\rightarrow BaCl_2+2H_2O\)

0,15                0,3             0,15

\(200ml=0,2l\\ C_{M_{HCl}}=\dfrac{0,3}{0,2}=1,5M\\ b.C_{M_{BaCl_2}}=\dfrac{0,15}{0,3+0,2}=0,3M\)

Đáp án D