Đề thiếu rồi bạn

\(n_{Ba\left(OH\right)_2}=0,075.0,1=0,0075\left(mol\right)\\ 2HCl+Ba\left(OH\right)_2\rightarrow BaCl_2+2H_2O\\ n_{HCl}=0,0075.2=0,015\left(mol\right)\\ C_{MddHCl}=\dfrac{0,015}{0,05}=0,3\left(M\right)\)

2HCl+Ba(OH)2->BaCl2+2H2O

n Ba(OH)2=0,1.0,075=0,0075 mol

=>n HCl=0,015 mol

=>CmHCl=0,015\0,05=0,3M

Câu 1:

PTHH: \(NaOH+HCl\rightarrow NaCl+H_2O\)

Ta có: \(n_{HCl}=0,2\cdot2=0,4\left(mol\right)=n_{NaOH}\)

\(\Rightarrow C_{M_{NaOH}}=\dfrac{0,4}{0,2}=2\left(M\right)\)

Câu 2: Bạn xem lại đề !!

Câu 2:

PTHH: \(NaOH+HCl\rightarrow NaCl+H_2O\)

Ta có: \(n_{NaOH}=\dfrac{200\cdot10\%}{40}=0,5\left(mol\right)=n_{HCl}\)

\(\Rightarrow m_{ddHCl}=\dfrac{0,5\cdot36,5}{3,65\%}=500\left(g\right)\)

Câu 3:

\(NaHCO_3+HCl\rightarrow NaCl+H_2O+CO_2\uparrow\)

\(Ca\left(OH\right)_2+HCl\rightarrow CaCl_2+H_2O\)

\(Na_2CO_3+2HCl\rightarrow2NaCl+H_2O+CO_2\uparrow\)

\(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\)

\(Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\)

*Các chất trên tác dụng tương tự với H₂SO₄ loãng 

Bonus:  \(Ba\left(NO_3\right)_2+H_2SO_4\rightarrow BaSO_4\downarrow+2HNO_3\)

\(\text{1)}m_{KOH}=40.35\%=14\left(g\right)\\ \rightarrow n_{KOH}=\dfrac{14}{56}=0,25\left(mol\right)\\ PTHH:KOH+HCl\rightarrow KCl+H_2O\\ \text{Theo pthh}:n_{HCl}=n_{KOH}=0,25\left(mol\right)\\ \rightarrow V_{ddHCl}=0,25.0,5=0,125\left(l\right)\)

\(\text{2)}n_{Al}=\dfrac{4,05}{27}=0,15\left(mol\right)\\ n_{H_2SO_4}=200.14,7\%=29,4\left(g\right)\\ \rightarrow n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\\ \text{PTHH}:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\\ \text{LTL}:\dfrac{0,15}{2}< \dfrac{0,3}{3}\rightarrow H_2SO_4\text{ dư}\)

\(\text{Theo pthh}:\left\{{}\begin{matrix}n_{H_2SO_4\left(pư\right)}=\dfrac{3}{2}n_{Al}=\dfrac{3}{2}.0,15=0,225\left(mol\right)\\n_{H_2}=n_{H_2SO_4\left(pư\right)}=0,225\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}.0,15=0,075\left(mol\right)\end{matrix}\right.\\ \rightarrow m_{dd\left(\text{sau phản ứng}\right)}=200+4,05-0,3.2=203,45\left(g\right)\)

\(\rightarrow\left\{{}\begin{matrix}C\%_{H_2SO_4\text{ dư}}=\dfrac{\left(0,3-0,225\right).98}{203,45}=3,61\%\\C\%_{Al_2\left(SO_4\right)_3}=\dfrac{342.0,075}{203,45}=12,61\%\end{matrix}\right.\)

Câu a thiếu đề em

B

Câu 2 : 

$n_{HCl} = 0,2.1 + 0,3.1,5 = 0,65(mol)$
$V_{dd} = 0,2 + 0,3 = 0,5(mol)$
$C_{M_{HCl}} = \dfrac{0,65}{0,5} =1,3M$

Câu 3 : 

Gọi $m_{H_2O\ cần\ thêm} =a (gam)$

Sau khi thêm : 

$m_{NaOH} = 100.35\% = 35(gam)$
$m_{dd} = 100 + a(gam)$

Suy ra:  $\dfrac{35}{100 + a}.100\% = 20\%$

Suy ra: a = 75(gam)

Câu 4 : 

Gọi $V_{dd\ HCl\ 2M} =a (lít) ; V_{dd\ HCl\ 3M} = b(lít)$

Ta có : 

$a + b = 4$
$2a + 3b = 4.2,75$

Suy ra a = 1(lít) ; b = 3(lít)