Đáp án A

n_CO2= 6,72/22,4= 0,3 mol;

n_Ca(OH)2= 0,4.1= 0,4 mol

Sau phản ứng thu được muối trung hòa CaCO₃

CO₂ + Ca(OH)₂ → CaCO₃ + H₂O

Ta có: 0,3 < 0,4 nên CO₂ phản ứng hết, Ca(OH)₂ còn dư

Ta có: n_CaCO3= n_CO2= 0,3 mol → m_CaCO3= 0,3.100= 30,0 gam 

a, \(Na_2SO_3+H_2SO_4\rightarrow Na_2SO_4+SO_2+H_2O\)

\(K_2SO_3+H_2SO_4\rightarrow K_2SO_4+SO_2+H_2O\)

Ta có: \(n_{SO_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

Theo PT: \(n_{H_2SO_4}=n_{SO_2}=0,3\left(mol\right)\)

\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,3.98}{20\%}=147\left(g\right)\)

b, Ta có: 126n_Na2SO3 + 158n_K2SO3 = 44,2 (1)

Theo PT: \(n_{SO_2}=n_{Na_2SO_3}+n_{K_2SO_3}=0,3\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{Na_2SO_3}=0,1\left(mol\right)\\n_{K_2SO_3}=0,2\left(mol\right)\end{matrix}\right.\)

Có: m _{dd sau pư} = 44,2 + 147 - 0,3.64 = 172 (g)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{Na_2SO_3}=\dfrac{0,1.126}{172}.100\%\approx7,33\%\\C\%_{K_2SO_3}=\dfrac{0,2.158}{172}.100\%\approx18,37\%\end{matrix}\right.\)

c, \(n_{Ba\left(OH\right)_2}=0,5.1=0,5\left(mol\right)\)

\(\Rightarrow\dfrac{n_{SO_2}}{n_{Ba\left(OH\right)_2}}=0,6< 1\) → Pư tạo BaSO₃.

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

\(n_{BaSO_3}=n_{SO_2}=0,3\left(mol\right)\Rightarrow m_{BaSO_3}=0,3.217=65,1\left(g\right)\)

\(n_{CO_2}=\dfrac{4.48}{22.4}=0.2\left(mol\right)\)

\(n_{Ca\left(OH\right)_2}=0.3\cdot1=0.3\left(mol\right)\)

\(T=\dfrac{0.2}{0.3}=0.67\rightarrow CaCO_3,Ca\left(OH\right)_2dư\)

\(n_{CaCO_3}=n_{CO_2}=0.2\left(mol\right)\)

\(m=0.2\cdot100=20\left(g\right)\)

Đáp án  D

n C O 2 = 0,2 mol; n C a ( O H ) 2 = 0,1 mol; n_NaOH = 0,1 mol; n O H - = 0,3 mol 

  T   =   n O H - n C O 2 = 0 , 3 0 , 2 = 1 , 5 → Tạo 2 loại muối : HCO₃^- và CO₃^2-

CO₂ + OH^- → HCO₃^-

x          x          x mol

CO₂ + 2OH^- → CO₃^2- + H₂O

y         2y            y mol

Có x+ y = 0,2; x+ 2y = 0,3 suy ra x = 0,1; y = 0,1

Ca²⁺ + CO₃^2- → CaCO₃↓

0,1        0,1 mol   0,1 mol

m C a C O 3 = 0,1. 100 = 10 gam

\(n_{SO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\ PTHH:SO_2+Ca\left(OH\right)_2\rightarrow CaSO_3\downarrow+H_2O\\ \Rightarrow n_{CaSO_3}=n_{SO_2}=0,1\left(mol\right)\\ \Rightarrow m_{CaSO_3}=120\cdot0,1=12\left(g\right)\)

\(n_{SO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

PTHH: SO₂ + Ca(OH)₂ → CaSO₃ + H₂O

Mol:     0,1                            0,1

\(m_{CaSO_3}=0,1.120=12\left(g\right)\)

1.

\(n_{CO_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)

\(n_{Ca\left(OH\right)_2}=0.075\left(mol\right)\)

\(T=\dfrac{0.1}{0.075}=1.33\)

=> Tạo ra 2 muối

\(n_{CaCO_3}=a\left(mol\right),n_{Ca\left(HCO_3\right)_2}=b\left(mol\right)\)

Khi đó :

\(a+b=0.075\)

\(a+2b=0.1\)

\(\Rightarrow\left\{{}\begin{matrix}a=0.05\\b=0.025\end{matrix}\right.\)

\(m_{sp}=0.05\cdot100+0.025\cdot162=9.05\left(g\right)\)

2.

\(n_{CO_2}=\dfrac{1.12}{22.4}=0.05\left(mol\right)\)

\(n_{Ba\left(OH\right)_2}=0.2\cdot0.2=0.04\left(mol\right)\)

\(T=\dfrac{0.005}{0.04}=1.25\)

=> Tạo ra 2 muối

\(n_{BaCO_3}=a\left(mol\right),n_{Ba\left(HCO_3\right)_2}=b\left(mol\right)\)

Ta có : 

\(a+b=0.04\)

\(a+2b=0.05\)

\(\Rightarrow\left\{{}\begin{matrix}a=0.03\\b=0.01\end{matrix}\right.\)

\(m_{BaCO_3}=0.03\cdot197=5.91\left(g\right)\)

\(n_{CO_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)

\(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

\(0.1...............0.1\)

\(C_{M_{Ca\left(OH\right)_2}}=\dfrac{0.1}{0.2}=0.5\left(M\right)\)

Đáp án A