Google
Câu hỏi: Trộn $100 \mathrm{ml}$ dung dịch $\text{AlC}{{\text{l}}_{3}} 1\text{M}$ với $200 \mathrm{ml}$ dung dịch $\text{NaOH} 1,8\text{M}$. Sau khi phản ứng kết thúc, khối lượng kết tủa thu được là
A. 3,12 gam.
B. 6,24 gam.
C. 1,56 gam.
D. 2,08 gam.
A. 3,12 gam.
B. 6,24 gam.
C. 1,56 gam.
D. 2,08 gam.
$\begin{aligned}
& \text{A}{{\text{l}}^{3+}}+3\text{O}{{\text{H}}^{-}}\to \text{Al}{{(\text{OH})}_{3}} \\
& x\quad 3x\quad x \\
\end{aligned}$
$\begin{aligned}
& \text{A}{{\text{l}}^{3+}}+4\text{O}{{\text{H}}^{-}}\to \text{Al}(\text{OH})_{4}^{-} \\
& y\quad 4y y \\
\end{aligned}$
$\left\{\begin{array}{l}x+y=0,1\left(n_{\mathrm{Al}^{3+}}\right) \\ 3 x+4 y=0,36\left(n_{\mathrm{OH}^{-}}\right)\end{array} \rightarrow\left\{\begin{array}{l}x=0,04 \\ y=0,06\end{array}\right.\right.$
$\rightarrow m_{\mathrm{Al}(\mathrm{OH})_{3}}=3,12$ gam.
& \text{A}{{\text{l}}^{3+}}+3\text{O}{{\text{H}}^{-}}\to \text{Al}{{(\text{OH})}_{3}} \\
& x\quad 3x\quad x \\
\end{aligned}$
$\begin{aligned}
& \text{A}{{\text{l}}^{3+}}+4\text{O}{{\text{H}}^{-}}\to \text{Al}(\text{OH})_{4}^{-} \\
& y\quad 4y y \\
\end{aligned}$
$\left\{\begin{array}{l}x+y=0,1\left(n_{\mathrm{Al}^{3+}}\right) \\ 3 x+4 y=0,36\left(n_{\mathrm{OH}^{-}}\right)\end{array} \rightarrow\left\{\begin{array}{l}x=0,04 \\ y=0,06\end{array}\right.\right.$
$\rightarrow m_{\mathrm{Al}(\mathrm{OH})_{3}}=3,12$ gam.
Đáp án A.