Bài 1:

\(2NaOH+SO_2\rightarrow Na_2SO_3+H_2O\\ NaOH+SO_2\rightarrow NaHSO_3\\ H_2S+2NaOH\rightarrow Na_2S+2H_2O\\ 2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ FeSO_4+2NaOH\rightarrow Fe\left(OH\right)_2+Na_2SO_4\)

Bài 2:

\(n_{HCl}=\dfrac{300.7,3\%}{36,5}=0,6\left(mol\right)\\ n_{NaOH}=\dfrac{200.4\%}{40}=0,2\left(mol\right)\\ NaOH+HCl\rightarrow NaCl+H_2O\\ m_{ddsau}=300+200=500\left(g\right)\\ Vì:\dfrac{0,2}{1}< \dfrac{0,6}{1}\\ \Rightarrow HCldư\\ C\%_{ddNaCl}=\dfrac{0,2.58,5}{500}.100=2,34\%\\ C\%_{ddHCl\left(dư\right)}=\dfrac{0,4.36,5}{500}.100=2,92\%\)

a, \(n_{Fe}=\dfrac{8,4}{56}=0,15\left(mol\right)\)

\(n_{HCl}=0,2.2=0,4\left(mol\right)\)

PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)

Xét tỉ lệ: \(\dfrac{0,15}{1}< \dfrac{0,4}{2}\), ta được HCl dư.

Theo PT: \(n_{H_2}=n_{Fe}=0,15\left(mol\right)\Rightarrow V_{H_2}=0,15.22,4=3,36\left(l\right)=3360\left(ml\right)\)

b, Theo PT: \(\left\{{}\begin{matrix}n_{FeCl_2}=n_{Fe}=0,15\left(mol\right)\\n_{HCl\left(pư\right)}=2n_{Fe}=0,3\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow n_{HCl\left(dư\right)}=0,4-0,3=0,1\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}C_{M_{FeCl_2}}=\dfrac{0,15}{0,2}=0,75\left(M\right)\\C_{M_{HCl\left(dư\right)}}=\dfrac{0,1}{0,2}=0,5\left(M\right)\end{matrix}\right.\)

c, Ta có: \(m_{ddHCl}=1,25.200=250\left(g\right)\)

⇒ m _{dd sau pư} = 8,4 + 250 - 0,15.2 = 258,1 (g)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{FeCl_2}=\dfrac{0,15.127}{258,1}.100\%\approx7,38\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,1.36,5}{258.1}.100\%\approx1,41\%\end{matrix}\right.\)

Bài 1 : 

$(1) 4Na + O_2 \xrightarrow{t^o} 2Na_2O$
$(2) Na_2O + 2HCl \to 2NaCl + H_2O$

$(3) 2NaCl + 2H_2O \xrightarrow{dpdd,cmn} 2NaOH + H_2+Cl_2$

$(4) NaOH + CO_2 \to NaHCO_3$

$(5) NaHCO_3 + HCl \to NaCl + CO_2 + H_2O$
$(6) CO_2 + Ca(OH)_2 \to CaCO_3 + H_2O$

Bài 2:

\(n_{SO_2}=\dfrac{16}{64}=0,25\left(mol\right)\\ n_{Ba\left(OH\right)_2}=\dfrac{17,1\%.300}{171}=0,3\left(mol\right)\\ Vì:\dfrac{n_{SO_2}}{n_{Ba\left(OH\right)_2}}=\dfrac{0,25}{0,3}< 1\)

=> Sau phản ứng thu được duy nhất muối trung hòa BaSO₃ và có dư Ba(OH)₂

\(Ba\left(OH\right)_2+SO_2\rightarrow BaSO_3\downarrow+H_2O\\ n_{Ba\left(OH\right)_2\left(dư\right)}=0,3-0,25=0,05\left(mol\right)\\ C\%_{ddBa\left(OH\right)_2\left(dư\right)}=\dfrac{171.0,05}{16+300-0,25.217}.100\approx3,266\%\)

Gọi số mol KHCO₃, K₂O là a, b (mol)

\(n_{BaCO_3}=\dfrac{11,82}{197}=0,06\left(mol\right)\)

Bảo toàn C: \(n_{KHCO_3\left(bđ\right)}=0,06\left(mol\right)\)

=> a = 0,06 (mol)

TH1: X chứa K₂CO₃, KOH

PTHH: K₂O + H₂O --> 2KOH

               b------------->2b

            KOH + KHCO₃ --> K₂CO₃ + H₂O

              0,06<--0,06----->0,06

=> X chứa \(\left\{{}\begin{matrix}K_2CO_3:0,06\left(mol\right)\\KOH:2b-0,06\left(mol\right)\end{matrix}\right.\)

Do 2 chất tan có cùng nồng độ mol

=> Số mol 2 chất tan bằng nhau

=> 2b - 0,06 = 0,06

=> b = 0,06 (mol)

m = 0,06.100 + 0,06.94 = 11,64 (g)

TH2: X chứa K₂CO₃, KHCO₃

PTHH: K₂O + H₂O --> 2KOH

              b------------->2b

            KOH + KHCO₃ --> K₂CO₃ + H₂O

              2b---->2b------->2b

=> X chứa \(\left\{{}\begin{matrix}KHCO_3:0,06-2b\left(mol\right)\\K_2CO_3:2b\left(mol\right)\end{matrix}\right.\)

=> 0,06 - 2b = 2b

=> b = 0,015 (mol)

=> m = 0,06.100 + 0,015.94 = 7,41 (g)

\(n_{H_2}\approx0,35\left(mol\right)\)

\(n_{Cl_2}=0,375\left(mol\right)\)

\(Fe+2HCl-->FeCl_2+H_2\uparrow\)

x.........2x........................x..............x

\(2M+2nHCl-->2MCl_n+nH_2\uparrow\)

4x..........4xn.................4x................2xn

\(2M+nCl_2-->2MCl_n\)

4x.......2xn...................4x

\(2Fe+3Cl_2-->2FeCl_3\)

x..........1,5x..............x

\(x+2xn=\dfrac{7,84}{22,4}\Rightarrow2xn=\dfrac{7,84}{22,4}-x\left(1\right)\)

\(2xn+1,5x=0,375\left(2\right)\)

thay(1) vaog(2) => x=0,05

n=3

Thể tích Cl2 tác dụng vs M

\(V_{Cl_2}=2.3.0,05.22,4=6,72\left(l\right)\)

b) \(M=\dfrac{5,4}{4.0,05}=27\left(\dfrac{g}{mol}\right)\)

=> M: Al

\(n_{H_2}=0,1\left(mol\right)\)

\(V_{HCl}=400\left(ml\right)=0,4\left(l\right)\)

\(Zn+2HCl-->ZnCl_2+H_2\uparrow\)

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

\(CM_{HCl}=\dfrac{0,2}{0,4}=0,5\left(M\right)\)

\(m_{ZnCl_2}=0,1.136=13,6\left(g\right)\)

b) \(n_{KOH}=\dfrac{50.22,4\%}{56.100\%}=0,2\left(mol\right)\)

\(n_{HCl}=0,2.0,5=0,1\left(mol\right)\)

\(HCl+KOH-->KCl+H_2O\)

\(\dfrac{0,1}{1}< \dfrac{0,2}{1}\) =>KOH dư

\(V_{KOH}=\dfrac{50}{1,25}=40\left(ml\right)=0,04\left(l\right)\)

\(CM_{KCl}=\dfrac{0,1}{0,2+0,04}=\dfrac{5}{12}\left(M\right)\)

\(CM_{KOH}=\dfrac{0,2-0,1}{0,2+0,04}=\dfrac{5}{12}\left(M\right)\)

MgCO3+2HCl\(\rightarrow\)MgCl2+H2O+CO2 (1)

de: 0,1 \(\leftarrow\) 0,2 \(\leftarrow\) 0,1 \(\leftarrow\) 0,1

MgO + 2HCl \(\rightarrow\) MgCl2 + H2O (2)

\(n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

\(m_{MgCO_3}=0,1.84=8,4g\)

\(\%m_{MgCO_3}=\dfrac{8,4}{10,4}.100\%\approx80,77\%\)

\(\%m_{MgO}=100-80,77\approx19,23\%\)

\(n_{MgO}=\dfrac{10,4-8,4}{40}=0,05\left(mol\right)\)

\(n_{HCl\left(2\right)}=0,05.2=0,1\left(mol\right)\)

\(m_{HCl}=36,5.\left(0,1+0,2\right)=10,95g\)

b, \(m_{ddHCl}=\dfrac{10,95}{7,3}.100=150g\)

\(n_{MgO}=n_{MgCl_2\left(2\right)}=0,05\left(mol\right)\)

\(m_{MgCl_2}=95.\left(0,05+0,1\right)=14,25g\)

\(m_{dd}=150+10,4-0,1.44=156g\)

\(C\%=\dfrac{14,25}{156}.100\%\approx9,135\%\)

a) $Fe + 2HCl \to FeCl_2 + H_2$

b)

n Fe = 8,4/56 = 0,15(mol) ; n HCl = 0,15.2,4 = 0,36(mol)

Ta thấy : 

n Fe / 1 < n HCl /2 nên HCl dư

Theo PTHH : n H2 = n Fe = 0,15 mol

=> V = 0,15.22,4 = 3,36 lít

c) Dung dịch chứa HCl,FeCl2

m dd HCl = D.V = 0,8.150 = 120(gam)

Sau phản ứng : 

n HCl dư = 0,36 - 0,15.2 = 0,06(mol)

n FeCl2 = n Fe = 0,15(mol)

m dd = 8,4 + 120 -0,15.2 = 128,1(gam)

C% HCl = 0,06.36,5/128,1   .100% = 1,71%

C% FeCl2 = 0,15.127/128,1   .100% = 14,87%

Em tham khảo, anh có làm rồi nè

$n_{SO_2} = \dfrac{16}{32} = 0,5(mol)$
$n_{Ba(OH)_2} = \dfrac{300.17,1\%}{171} = 0,3(mol)$

\(SO_2+Ba\left(OH\right)_2\rightarrow BaSO_3+H_2O\)

a                   a                  a                                   (mol)

\(2SO_2+Ba\left(OH\right)_2\rightarrow Ba\left(HSO_3\right)_2\)

2b                 b                    b                                 (mol)

Ta có:  

$a + b = 0,3$

$a + 2b = 0,5$

Suy ra : a = 0,1 ; b = 0,2

$m_{dd} = 16 + 300 - 0,1.217 = 294,3(gam)$
$C\%_{Ba(HSO_3)_2} = \dfrac{0,2.299}{294,3}.100\% = 20,32\%$

\(n_{SO_2}=\dfrac{16}{64}=0,25\left(mol\right)\)

\(m_{Ba\left(OH\right)_2}=300.17,1\%=51,3\left(g\right)\Rightarrow n_{Ba\left(OH\right)_2}=\dfrac{51,3}{171}=0,3\left(mol\right)\)

PTHH: SO₂ + Ba(OH)₂ → BaSO₃ + H₂O

Mol:     0,25     0,25             0,25

Ta có: \(\dfrac{0,25}{1}< \dfrac{0,3}{1}\) ⇒ SO₂ pứ hết, Ba(OH)₂ dư

m_{dd sau pứ} = 16+300 = 316 (g)

\(C\%_{ddBaSO_3}=\dfrac{0,25.217.100\%}{316}=17,17\%\)

\(C\%_{ddBa\left(OH\right)_2dư}=\dfrac{\left(0,3-0,25\right).171.100\%}{316}=2,7\%17,17\%\)