bai 1 ne 

\(a.n_{Mg\left(OH\right)_2}=\dfrac{17,4}{58}=0,3\left(mol\right)\\ Mg\left(OH\right)_2+2HCl\rightarrow MgCl_2+2H_2O\\ n_{HCl}=2n_{Mg\left(OH\right)_2}=0,6\left(mol\right)\\ CM_{HCl}=\dfrac{0,6}{0,2}=3M\\b. n_{Mg\left(OH\right)_2}=n_{MgCl_2}=0,3\left(mol\right)\\ m_{MgCl_2}=0,3.85=25,5\left(g\right)\\c.CM_{MgCl_2}=\dfrac{0,3}{0,2}=1,5M \)

200ml = 0,2l

\(n_{Ba\left(OH\right)2}=0,5.0,2=0,1\left(mol\right)\)

Pt : \(Ba\left(OH\right)_2+2HCl\rightarrow BaCl_2+2H_2O|\)

              1              2             1            2

             0,1           0,2          0,1

a) \(n_{HCl}=\dfrac{0,1.2}{1}=0,2\left(mol\right)\)

\(V_{ddHCl}=\dfrac{0,2}{1}=0,2\left(l\right)=200\left(ml\right)\)

b) \(n_{BaCl2}=\dfrac{0,2.1}{2}=0,1\left(mol\right)\)

⇒ \(m_{BaCl2}=0,1.208=20,8\left(g\right)\)

c) \(V_{ddspu}=0,2+0,2=0,4\left(l\right)\)

\(C_{M_{BaCl2}}=\dfrac{0,1}{0,4}=0,25\left(M\right)\)

 Chúc bạn học tốt

PTHH: \(Ba\left(OH\right)_2+2HCl\rightarrow BaCl_2+2H_2O\)

Ta có: \(n_{Ba\left(OH\right)_2}=0,2\cdot0,5=0,1\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=0,2\left(mol\right)\\n_{BaCl_2}=0,1\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{ddHCl}=\dfrac{0,2}{1}=0,2\left(l\right)=200\left(ml\right)\\m_{BaCl_2}=0,1\cdot208=20,8\left(g\right)\\C_{M_{BaCl_2}}=\dfrac{0,1}{0,2+0,2}=0,25\left(M\right)\end{matrix}\right.\)

a, \(NaHCO_3+NaOH\rightarrow Na_2CO_3+H_2O\)

\(HCO_3^-+OH^-\rightarrow CO_3^{2-}+H_2O\)

b, \(\left[Na^+\right]=\dfrac{0,2.1,5+0,12.1,6}{0,2+0,12}=1,5376M\)

\(\left[CO_3^{2-}\right]=\dfrac{0,2.1,5}{0,2+0,12}=0,9375M\)

\(n_{H^+}=0,3\left(mol\right)\)

\(n_{OH^-}=0,192\left(mol\right)\)

\(\Rightarrow n_{H^+dư}=0,108\left(mol\right)\)

\(\Rightarrow\left[H^+\right]=\dfrac{0,108}{0,2+0,12}=0,3375M\)

\(\Rightarrow pH\approx0,47\)

a) \(n_{NaOH}=0,2.1=0,2\left(mol\right)\); \(n_{HNO_3}=0,2.0,5=0,1\left(mol\right)\)

\(NaOH+HNO_3\rightarrow NaNO_3+H_2O\)

0,2.............0,1

Lập tỉ lệ : \(\dfrac{0,2}{1}>\dfrac{0,1}{1}\) => Sau phản ứng NaOH dư

Dung dịch D gồm NaNO3 và NaOH dư

\(n_{NaNO_3}=n_{HNO_3}=0,1\left(mol\right)\)

\(n_{NaOH\left(pứ\right)}=n_{HNO_3}=0,1\left(mol\right)\)

\(n_{NaOH\left(dư\right)}=0,2-0,1=0,1\left(mol\right)\)

Ion trong dung dịch D : Na+ , NO3-, OH-

\(\left[Na^+\right]=\dfrac{0,1+0,1}{0,2}=1M\)

\(\left[NO_3^-\right]=\dfrac{0,1}{0,2}=0,5M\)

\(\left[OH^-\right]=\dfrac{0,1}{0,2}=0,5M\)

b)Trong dung dịch D chỉ có NaOH dư phản ứng

 \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+H_2O\)

0,1................0,05

=> \(V_{H_2SO_4}=\dfrac{0,05}{1}=0,05\left(l\right)\)

Tách ra lần bài đi em !

\(n_{NaCl}=0,1.0,2=0,02\left(mol\right)\)

\(m_{Na_2CO_3}=0,1.0,3=0,03\left(mol\right)\)

\(\left\{{}\begin{matrix}n_{Na^+}=0,02+0,03.2=0,08\left(mol\right)\\n_{Cl^-}=0,02\left(mol\right)\\n_{CO_3^{2-}}=0,03\left(mol\right)\end{matrix}\right.\)

=> \(\left\{{}\begin{matrix}C_{M\left(Na^+\right)}=\dfrac{0,08}{0,2+0,3}=0,16M\\C_{M\left(Cl^-\right)}=\dfrac{0,02}{0,2+0,3}=0,04M\\C_{M\left(CO_3^{2-}\right)}=\dfrac{0,03}{0,2+0,3}=0,06M\end{matrix}\right.\)