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\(n_{HCl}=0.2\cdot0.1=0.02\left(mol\right)\)
\(\Rightarrow n_{OH^-}=0.02\cdot2=0.04\left(mol\right)\)
BTĐT :
\(b=0.04+0.01-0.01\cdot2=0.03\left(mol\right)\)
\(m_{Cr}=0.01\cdot137+0.01\cdot62+0.04\cdot17+0.03\cdot23=3.36\left(g\right)\)
Theo ĐLBT điện tích thì: 0,01.2+ b = 0,01+a
H+ + OH- → H2O
nOH-= nH+= 0,04 mol = a => b = 0,03 mol
Khối lượng chất rắn thu được khi cô cạn dung dịch X là:
0,01.137+ 0,01.62+ 17.0,04+ 23.0,03 = 3,36 gam
\(n_{NaOH}=0.1\cdot0.1=0.01\left(mol\right)\)
\(n_{KOH}=0.1\cdot0.1=0.01\left(mol\right)\)
\(V=0.1+0.1=0.2\left(l\right)\)
\(\left[Na^+\right]=\dfrac{0.01}{0.2}=0.05\left(M\right)\)
\(\left[K^+\right]=\dfrac{0.01}{0.2}=0.05\left(M\right)\)
\(\left[OH^-\right]=\dfrac{0.01+0.01}{0.2}=0.1\left(M\right)\)
\(b.\)
\(pH=14+log\left[OH^-\right]=14+log\left(0.1\right)=13\)
\(c.\)
\(H^++OH^-\rightarrow H_2O\)
\(0.02........0.02\)
\(V_{dd_{H_2SO_4}}=\dfrac{0.02}{1}=0.02\left(l\right)\)
\(a.\)
\(n_{NaOH}=0.1\cdot0.1=0.01\left(mol\right)\)
\(n_{KOH}=0.1\cdot0.1=0.01\left(mol\right)\)
\(V=0.1+0.1=0.2\left(l\right)\)
\(\left[Na^+\right]=\dfrac{0.01}{0.2}=0.05\left(M\right)\)
\(\left[K^+\right]=\dfrac{0.01}{0.2}=0.05\left(M\right)\)
\(\left[OH^+\right]=\dfrac{0.01+0.01}{0.2}=0.1\left(M\right)\)
\(b.\)
\(pH=14+log\left(0.1\right)=13\)
\(c.\)
\(H^++OH^-\rightarrow H_2O\)
\(0.02.......0.02\)
\(V_{H_2SO_4}=\dfrac{0.02}{1}=0.02\left(l\right)\)
a) Ta có: \(n_{NaOH}=0,1\cdot0,1=n_{KOH}=0,01\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{OH^-}=0,02\left(mol\right)\\n_{Na^+}=n_{K^+}=0,01\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\left[OH^-\right]=\dfrac{0,02}{0,2}=0,1\left(M\right)\\\left[Na^+\right]=\left[K^+\right]=\dfrac{0,01}{0,2}=0,05\left(M\right)\end{matrix}\right.\)
b) Ta có: \(pH=14+log\left[OH^-\right]=13\)
c) PT ion: \(OH^-+H^+\rightarrow H_2O\)
Theo PT ion: \(n_{H^+}=n_{OH^-}=0,02\left(mol\right)\)
\(\Rightarrow n_{H_2SO_4}=0,01\left(mol\right)\) \(\Rightarrow V_{ddH_2SO_4}=\dfrac{0,01}{1}=0,01\left(l\right)=10\left(ml\right)\)
So mol H+ = 0,4VA. Số mol OH- = 0,05
=> pH = 7 nên pư vừa đủ => 0,4VA = 0,05 => VA = 0,125 lít = 125 ml
\(pH=2\Rightarrow\left[H^+_{dư}\right]=10^{-2}\Rightarrow n_{H^+}=10^{-2}\left(V+0,4\right)\)
\(n_{H^+}=2.0,0375.0,4+0,0125.0,4=0,035\left(mol\right)\)
\(n_{OH^-}=0,3V\left(mol\right)\)
\(\Rightarrow0,035+0,3V=10^{-2}\left(V+0,4\right)\)
\(\Rightarrow V=33,1\left(l\right)\)
\(\Leftrightarrow V=\)
nOH- = (0,2 + 0,1.2)V = 0,4V; nH+ = (0,25.2 + 0,75).0,04 = 0,05
Do trung hòa nên nOH- = nH+ → 0,4V = 0,05 → V = 0,125 lít
Đáp án B
Có:nH2SO4 =0,02(mol) ; nHCl=0,04(mol)
=>nH(+)=0,08(mol)
Có: nBa(OH)2 =0,045 (mol); nNaOH=0,03(mol)
=>nOH(-)=0,12(mol)
H(+) +OH(-) ------>H2O
0,008-----0,008
=>nOH(-) dư=0,04(mol)
[OH(-) dư]=0,04/0,5=0,08(M)
=>pH= -log(0,08) =1,1
a, \(\left[Na^+\right]=0,1\)
\(\left[K^+\right]=0,1\)
\(\left[OH^-\right]=0,2\)
\(\left[SO_4^{2-}\right]=0,2\)
\(\left[H^+\right]=0,4\)
b, \(n_{H^+}=0,1.0,4=0,04\left(mol\right)\)
\(n_{OH^-}=0,1.0,2=0,02\left(mol\right)\)
\(H^++OH^-\rightarrow H_2O\)
\(\Rightarrow n_{H^+dư}=0,02\left(mol\right)\)
\(\Rightarrow\left[H^+\right]=\dfrac{0,02}{200}=10^{-4}\)
\(\Rightarrow pH=4\)
nOH-=0,05.2.0,2+ 0,1.0,2=0,04 mol
nH+=0,1.V.2+ 0,2.V=0,4V mol
H++OH--->H2O
nH+=nOH-=> 0,4v=0,04-> v=0,1 lit = 100ml