the tich dd HCL 0,4M can dung de trung hoa het 200ml dd NaOH 0,3M la:
A:150 ml B:250ml C:200 ml D:100 ml
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\(a.n_{NaOH}=1.0,15=0,15\left(mol\right)\\ n_{KOH}=0,5.0,1=0,05\left(mol\right)\\ \left[Na^+\right]=\left[NaOH\right]=\dfrac{0,15}{0,15+0,1}=0,6\left(M\right)\\ \left[K^+\right]=\left[KOH\right]=\dfrac{0,05}{0,1+0,15}=0,2\left(M\right)\\ \left[OH^-\right]=0,2+0,6=0,8\left(M\right)\\ b.2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\\ 2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ n_{H_2SO_4}=\dfrac{1}{2}.\left(n_{KOH}+n_{NaOH}\right)=\dfrac{0,15+0,05}{2}=0,1\left(mol\right)\\ a=C_{MddH_2SO_4}=\dfrac{0,1}{0,2}=0,5\left(M\right)\)
axit mạnh tác dụng với bazo mạnh là phản ứng hoàn toàn , số mol NaOH = HCl , bài này dạng căn bản bạn tự làm nhé
\(b.n_{NaOH\left(tổng\right)}=0,4.0,5+\dfrac{100.1,33.20\%}{40}=0,865\left(mol\right)\\ \left[Na^+\right]=\left[OH^-\right]=\left[NaOH\left(sau\right)\right]=\dfrac{0,865}{0,4+0,1}=1,73\left(M\right)\\ c.n_{HCl}=0,05.0,12=0,006\left(mol\right)\\ n_{HNO_3}=0,15.0,1=0,015\left(mol\right)\\ \left[H^+\right]=\dfrac{0,006+0,015}{0,05+0,15}=0,105\left(M\right)\\ \left[NO^-_3\right]=\dfrac{0,015}{0,05+0,15}=0,075\left(M\right)\\ \left[Cl^-\right]=\dfrac{0,006}{0,05+0,15}=0,03\left(M\right)\)
\(d.n_{H_2SO_4}=0,4.0,05=0,02\left(mol\right)\\ n_{HCl}=0,35.0,2=0,07\left(mol\right)\\ \left[H^+\right]=\dfrac{0,02.2+0,07}{0,05+0,35}=0,275\left(M\right)\\ \left[SO^{2-}_4\right]=\dfrac{0,02}{0,05+0,35}=0,05\left(M\right)\\ \left[Cl^-\right]=\dfrac{0,07}{0,05+0,35}=0,175\left(M\right)\\ f.n_{KOH}=\dfrac{20.1,31.32\%}{56}=\dfrac{131}{875}\left(mol\right)\\ n_{Ba\left(OH\right)_2}=0,08.1=0,08\left(mol\right)\\ \left[OH^-\right]=\dfrac{\dfrac{131}{875}+0,08.2}{0,02+0,08}=\dfrac{542}{175}\left(M\right)\\ \left[Ba^{2+}\right]=\dfrac{0,08}{0,02+0,08}=0,8\left(M\right)\)
\(\left[K^+\right]=\dfrac{\dfrac{131}{875}}{0,02+0,08}=\dfrac{262}{175}\left(M\right)\)
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 :(
Câu 1:
PT ion: \(H^++OH^-\rightarrow H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{OH^-}=0,6\cdot0,4+0,6\cdot0,3\cdot2=0,6\left(mol\right)\\n_{H^+}=0,2\cdot2,6=0,52\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\) H+ hết, OH- còn dư \(\Rightarrow n_{OH^-\left(dư\right)}=0,08\left(mol\right)\)
\(\Rightarrow\left[OH^-\right]=\dfrac{0,08}{0,6+0,2}=0,1\left(M\right)\) \(\Rightarrow pH=14+log\left(0,1\right)=13\)
Bài 2:
PT ion: \(H^++OH^-\rightarrow H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{OH^-}=0,3\cdot1,6=0,48\left(mol\right)\\n_{H^+}=0,2\cdot1\cdot2+0,2\cdot2=0,8\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\) OH- hết, H+ còn dư \(\Rightarrow n_{H^+\left(dư\right)}=0,32\left(mol\right)\)
\(\Rightarrow\left[H^+\right]=\dfrac{0,32}{0,2+0,3}=0,64\left(M\right)\) \(\Rightarrow pH=-log\left(0,64\right)\approx0,19\)
nH2SO4 = 0.2*1=0.2 mol
2NaOH + H2SO4 --> Na2SO4 + H2O
0.4________0.2
mNaOH = 0.4*40=16g
2KOH + H2SO4 --> K2SO4 + H2O
0.4______0.2
mKOH= 0.4*56=22.4g
mddKOH = 22.4*100/5.6=400g
VddKOH = 400/1.045=382.77ml
\(n_{H_2SO_4}=0,2\times1=0,2\left(mol\right)\)
H2SO4 + 2NaOH → Na2SO4 + 2H2O (1)
a) Theo PT1: \(n_{NaOH}=2n_{H_2SO_4}=2\times0,2=0,4\left(mol\right)\)
\(\Rightarrow m_{NaOH}=0,4\times40=16\left(g\right)\)
b) H2SO4 + 2KOH → K2SO4 + 2H2O (2)
Theo PT2: \(n_{KOH}=2n_{H_2SO_4}=2\times0,2=0,4\left(mol\right)\)
\(\Rightarrow m_{KOH}=0,4\times56=22,4\left(g\right)\)
\(\Rightarrow m_{ddKOH}=\frac{22,4}{5,6\%}=400\left(g\right)\)
\(\Rightarrow V_{ddKOH}=\frac{400}{1,045}=382,78\left(ml\right)\)
Gọi thể tích dd A là V(lít)
=> nHCl=0,4V mol, nH2SO4= 0,3V mol
=>\(\sum_{H^+}=\)0,4V+0,3V*2=1*V=V(mol)
DD B có nNaOH=2*0,2=0,4mol, nBa(OH)2=0,5*0,2=0,1mol
=>\(\sum_{OH^-}=\)0,4+0,1*2=0,6 mol
Pứ trung hòa:
__H+ + _OH- → H2O
___0,6<--0,6 (mol)
Mà nH+ =V => V=0,6 lít
NaOH+HCl-->NaCl+H2O
nNaOH=V.M=0,2.0,3=0,06(mol)
-->nHcl=0,06(mol)
VHCl=\(\dfrac{0,06}{0,4}\)=0,15(l)=150(ml)