$NaNO_3 \to Na^+ + NO_3^-$
$Na_2SO_4 \to 2Na^+ + SO_4^{2-}$

$NaCl \to Na^+ + Cl^-$

Ta có : 

$[Na^+] = 0,1 + 0,02.2 + 0,3 = 0,44M$

a) Ta có: \(n_{Al\left(NO_3\right)_3}=\dfrac{4,26}{213}=0,02\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}n_{Al^+}=0,02\left(mol\right)\\n_{NO_3^-}=0,06\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\left[Al^+\right]=\dfrac{0,02}{0,1}=0,2\left(M\right)\\\left[NO_3^-\right]=\dfrac{0,06}{0,1}=0,6\left(M\right)\end{matrix}\right.\)

b) Ta có: \(\left[Na^+\right]=0,1+0,02\cdot2+0,3=0,304\left(M\right)\)

c) Bạn xem lại đề !!

Đáp án C

n N a 2 S O 4 = 0,02 mol; n_NaCl=0,5 mol; n_Na+= 0,02.2+0,5= 0,54 mol

[Na⁺]= 0,54/(0,117+0,171+0,212)= 1,08M

Chọn C

Trong các chất trên chỉ có CH 3 COOH là chất điện li yếu nên có tổng nồng độ mol của các ion là nhỏ nhất.

Câu 3 : 

\(pH=-log\left[H^+\right]=-log\left(0.1\right)=1\)

Câu 4 : 

Chứa các ion : H⁺ , Cl^-

Câu 5 : 

\(n_{NaOH}=n_{HCl}=0.02\cdot0.1=0.002\left(mol\right)\)

\(\Rightarrow x=\dfrac{0.002}{0.01}=0.2\left(M\right)\)

Câu 1 : 

Bảo toàn điện tích : 

\(n_{SO_4^{2-}}=\dfrac{0.2\cdot2+0.1-0.05}{2}=0.225\left(mol\right)\)

\(m_{Muối}=0.2\cdot64+0.1\cdot39+0.05\cdot35.5+0.225\cdot96=40.075\left(g\right)\)

Câu 2 : 

\(\left[Na^+\right]=\dfrac{0.15\cdot0.5\cdot2+0.05\cdot1}{0.15+0.05}=1\left(M\right)\)

Câu 6 : 

\(pH=14+log\left[OH^-\right]=12\)

\(\Rightarrow\left[OH^-\right]=0.01\)

\(n_{NaOH}=n_{OH}=0.01\cdot2=0.02\left(mol\right)\)

\(\Rightarrow m_{NaOH\left(bđ\right)}=0.02\cdot40=0.8\left(g\right)\)

Câu 7 : 

\(n_{KOH}=0.25\cdot0.03=0.0075\left(mol\right)\)

\(n_{HCl}=0.25\cdot0.01=0.0025\left(mol\right)\)

\(\Rightarrow n_{KOH\left(dư\right)}=0.0075-0.0025=0.005\left(mol\right)\)

\(\left[OH^-\right]=\dfrac{0.005}{0.25+0.25}=0.01\)

\(pH=14+log\left[OH^-\right]=14+log\left(0.01\right)=12\)

\(n_{H^+}=0,1.2.0,2=0,04\Rightarrow\left[H^+\right]=\dfrac{0,04}{0,2+0,1}\approx0,13M\)

\(n_{SO_4^{2-}}=0,2.0,1+0,3.0,1=0,05\Rightarrow\left[SO_4^{2-}\right]=\dfrac{0,05}{0,2+0,1}\approx0,17M\)

\(n_{Na^+}=0,3.0,1.2=0,06\Rightarrow\left[Na^+\right]=\dfrac{0,06}{0,2+0,1}\approx0,2M\)

a)
$BaCl_2 + Na_2SO_4 \to BaSO_4 + 2NaCl$

$n_{BaCl_2} = 0,01 = n_{Na_2SO_4} = 0,01 \Rightarrow $ Vừa đủ

$n_{BaSO_4} = n_{Na_2SO_4} = 0,01(mol)$
$m_{BaSO_4} = 0,01.233 = 0,233(gam)$
b)

$n_{NaCl} = 2n_{Na_2SO_4} = 0,02(mol)$
$V_{dd} = 0,1 + 0,2 = 0,3(lít)$
$C_{M_{NaCl}} = \dfrac{0,02}{0,3} = 0,067M$

c)

$[Na^+] = [Cl^-] = C_{M_{NaCl}} = 0,067M$

\(n_{BaCl_2}=0.1\cdot0.1=0.01\left(mol\right)\)

\(n_{Na_2SO_4}=0.2\cdot0.05=0.01\left(mol\right)\)

\(BaCl_2+Na_2SO_4\rightarrow BaSO_4+2NaCl\)

\(0.01..........0.01............0.01..............0.02\)

\(m_{BaSO_4}=0.01\cdot233=2.33\left(g\right)\)

\(C_{M_{NaCl}}=\dfrac{0.01}{0.1+0.2}=0.03\left(M\right)\)

\(\left[Na^+\right]=\left[Cl^-\right]=0.03\left(M\right)\)

\(n_{NaCl}=0.1\cdot0.1=0.01\left(mol\right)\)

\(n_{AgNO_3}=0.15\cdot0.1=0.015\left(mol\right)\)

\(NaCl+AgNO_3\rightarrow NaNO_3+AgCl\)

\(0.01..........0.01...............0.01\)

Dung dịch : 0.01 (mol) NaNO₃ , 0.005 (mol) AgNO₃

\(\left[Na^+\right]=\dfrac{0.01}{0.1+0.15}=0.04\left(M\right)\)

\(\left[Ag^+\right]=\dfrac{0.005}{0.25}=0.02\left(M\right)\)

\(\left[NO_3^-\right]=\dfrac{0.01+0.005}{0.25}=0.06\left(M\right)\)