nNaOH = 0,1.0,2 = 0,02 mol => nOH^- = 0,02 mol

nCa(OH)₂ = 0,1.0,2 = 0,02 mol => nOH^- = 0,02.2 = 0,04 mol

=> Sau khi trộn nOH^- = 0,02 + 0,04 = 0,06 mol

Thể tích dung dịch sau khi trộn = 100 + 200 = 300ml = 0,3 lít

=> [OH^-] = \(\dfrac{0,06}{0,3}\)= 0,2 M

\(n_{NaOH}=0.25\cdot2=0.5\left(mol\right)\)

\(n_{H_2SO_4}=0.25\cdot1=0.25\left(mol\right)\)

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

\(0.5..............0.25................0.25\)

\(\left[Na^+\right]=\dfrac{0.25\cdot2}{0.25+0.25}=1\left(M\right)\)

\(\left[SO_4^{2-}\right]=\dfrac{0.25}{0.25+0.25}=0.5\left(M\right)\)

Ok, để thử coi chứ tui ngu hóa thấy mồ :(

a/ \(n_{NaOH}=0,2.0,1=0,02\left(mol\right)\)

\(NaOH\rightarrow Na^++OH^-\)

\(n_{Na^+}=n_{OH^-}=0,02\left(mol\right)\)

\(\Rightarrow C_{MNa^+}=\frac{0,02}{0,4+0,1}=0,04\left(mol/l\right)\)

\(n_{Ba\left(OH\right)_2}=0,3.0,4=0,12\left(mol\right)\)

\(Ba\left(OH\right)_2=Ba^{2+}+2OH^-\)

\(\Rightarrow n_{OH^-}=0,24\left(mol\right);n_{Ba^{2+}}=0,12\left(mol\right)\)

\(\Rightarrow C_{MBa^{2+}}=\frac{0,12}{0,5}=0,24\left(mol/l\right)\)

\(n_{OH^-}=0,02+0,24=0,26\left(mol\right)\)

\(\Rightarrow C_{MOH^-}=\frac{0,26}{0,5}=0,52\left(mol/l\right)\)

b/ \(n_{HCl}=0,2V\left(mol\right)\)

\(\Rightarrow n_{H^+}=n_{Cl^-}=0,2V\)

\(\Rightarrow C_{MCl^-}=\frac{0,2V}{2V}=0,1\left(mol/l\right)\)

\(n_{H_2SO_4}=0,3V\left(mol\right)=\frac{n_{H^+}}{2}=n_{SO_4^{2-}}\)

\(\Rightarrow C_{MSO_4^{2-}}=\frac{0,3V}{2V}=0,15\left(mol/l\right)\)

\(n_{H^+}=0,2V+0,6V=0,8V\left(mol\right)\)

\(\Rightarrow C_{MH^+}=\frac{0,8V}{2V}=0,4\left(mol/l\right)\)

Bác nào hảo tâm giúp em mấy câu còn lại chớ đến đây thì em chịu chết òi :(

\(n_{FeCl_3}=0,1.0,1=0,01mol\)

\(n_{NaOH}=0,4.0,1=0,04mol\)

FeCl₃+3NaOH\(\rightarrow\)Fe(OH)₃\(\downarrow\)+3NaCl

-Tỉ lệ: \(\dfrac{0,01}{1}< \dfrac{0,04}{3}\)\(\rightarrow\)FeCl₃ hết, NaOH dư

\(n_{NaOH\left(pu\right)}=3n_{FeCl_3}=0,03mol\)

\(n_{NaOH\left(dư\right)}=0,04-0,03=0,01mol\)

\(n_{NaCl}=3n_{FeCl_3}=0,03mol\)

-Dung dịch D có NaCl 0,03 mol và NaOH dư 0,01 mol

[Na⁺]=\(\dfrac{0,03+0,01}{0,1+0,4}=0,08M\)

[Cl^-]=\(\dfrac{0,03}{0,5}=0,06M\)

[OH^-]=\(\dfrac{0,01}{0,5}=0,02M\)

\(n_{Fe\left(OH\right)_3}=n_{FeCl_3}=0,01mol\)

m=\(m_{Fe\left(OH\right)_3}=0,01.107=1,07g\)

a) ko bik ....

b) 13,5

c)2

d)2,4

a, \(\left[Ca^{2+}\right]=\dfrac{0,15.0,5}{0,15+0,05}=0,375M\)

\(\left[Na^+\right]=\dfrac{0,05.2}{0,15+0,05}=0,5M\)

\(\left[Cl^-\right]=\dfrac{0,15.2.0,5+0,05.2}{0,15+0,05}=1,25M\)

b, \(\left[Fe^{3+}\right]=\dfrac{\dfrac{2.1,6}{400}}{1,5}\approx0,005M\)

\(\left[K^+\right]=\dfrac{\dfrac{2.6,96}{174}}{1,5}\approx0,053M\)

\(\left[SO_4^{2-}\right]=\dfrac{\dfrac{3.1,6}{400}+\dfrac{6,96}{174}}{1,5}\approx0,035M\)

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 !

\(n_{KOH}=0.1\cdot1=0.1\left(mol\right)\)

\(n_{H_2SO_4}=0.3\cdot0.5=0.15\left(mol\right)\)

\(2KOH+H_2SO_4\rightarrow K_2SO_4+H_2O\)

\(0.1..........0.05...............0.05\)

Dung dịch D : 0.05 (mol) K₂SO₄ , 0.1 (mol) H₂SO₄

\(\left[K^+\right]=\dfrac{0.05\cdot2}{0.1+0.3}=0.25\left(M\right)\)

\(\left[H^+\right]=\dfrac{0.1\cdot2}{0.1+0.3}=0.5\left(M\right)\)

\(\left[SO_4^{2-}\right]=\dfrac{0.05+0.1}{0.1+0.3}=0.375\left(M\right)\)

\(2NaOH+H_2SO_4\rightarrow K_2SO_4+H_2O\)

\(0.2..................0.1\)

\(V_{dd_{NaOH}}=\dfrac{0.2}{1}=0.2\left(l\right)\)