Chọn D

V H 2 S O 4 = n H 2 S O 4 C M = 0,25 2 = 0,125 ( l ) = 125 m l .

\(m_{HCl}=\dfrac{300.7,3\%}{100\%}=21,9g\\ n_{HCl}=\dfrac{21,9}{36,5}=0,6mol\\ HCl+NaOH\rightarrow NaCl+H_2O\left(1\right)\\ n_{NaOH\left(1\right)}=n_{HCl}=0,6mol\\ m_{H_2SO_4}=\dfrac{200.9,8\%}{100\%}=19,6g\\ n_{H_2SO_4}=\dfrac{19,6}{98}=0,2mol\\ H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\left(2\right)\\ n_{NaOH\left(2\right)}=0,2.2=0,4mol\\ n_{NaOH}=0,4+0,6=1mol\\ m_{NaOH}=1.40=40g\\ m_{ddNaOH}=\dfrac{40}{5\%}\cdot100\%=800g\)

500ml = 0,5l

\(n_{NaOH}=1.0,5=0,5\left(mol\right)\)

Pt : \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O|\)

            2                1                1              2

          0,5             0,25

\(n_{H2SO4}=\dfrac{0,5.1}{2}=0,25\left(mol\right)\)

\(V_{ddH2SO4}=\dfrac{0,25}{2}=0,125\left(l\right)\)

 Chúc bạn học tốt

2NaOH+H2SO4 -> Na2SO4+2H2O

n(NaOH)=0,5.1=0,5(mol)

Theo PTHH: n(H2SO4)=n(NaOH)/2

=> n(H2SO4)=0,25(mol)

=> V(H2SO4)=0,25/2=0,125l

a) 2NaOH + H₂SO₄ --> Na₂SO₄ + 2H₂O

b) \(m_{NaOH}=\dfrac{200.8}{100}=16\left(g\right)\)

=> \(n_{NaOH}=\dfrac{16}{40}=0,4\left(mol\right)\)

PTHH: 2NaOH + H₂SO₄ --> Na₂SO₄ + 2H₂O

                0,4--->0,2--------->0,2

=> \(m_{Na_2SO_4}=0,2.142=28,4\left(g\right)\)

c) \(m_{H_2SO_4}=0,2.98=19,6\left(g\right)\)

=> \(m_{dd.H_2SO_4}=\dfrac{19,6.100}{9,8}=200\left(g\right)\)

mNaOH = 8% . 200 = 16 (g)

nNaOH = 16/40 = 0,4 (mol)

PTHH: 2NaOH + H2SO4 -> Na2SO4 + 2H2O 

Mol: 0,4 ---> 0,2 ---> 0,2 ---> 0,4

mNa2SO4 = 0,2 . 119 = 23,8 (g)

mH2SO4 = 0,2 . 98 = 19,6 (g)

mddH2SO4 = 19,6/9,8% = 200 (g)

Đáp án C

Khối lượng chất rắn khan thu được khi cô cạn dung dịch Z là

PTHH: \(Ba\left(OH\right)_2+H_2SO_4\rightarrow BaSO_4\downarrow+2H_2O\)

Ta có: \(n_{Ba\left(OH\right)_2}=0,5\cdot1=0,5\left(mol\right)=n_{BaSO_4}=n_{H_2SO_4}\)

\(\Rightarrow\left\{{}\begin{matrix}m_{ddH_2SO_4}=\dfrac{0,5\cdot98}{15\%}\approx326,7\left(g\right)\\m_{BaSO_4}=0,5\cdot233=116,5\left(g\right)\end{matrix}\right.\)

\(n_{Ba\left(OH\right)_2}=0,5\cdot1=0,5mol\)

a)\(Ba\left(OH\right)_2+H_2SO_4\rightarrow BaSO_4\downarrow+2H_2O\)

    0,5                 0,5            0,5        

b) \(m_{H_2SO_4}=0,5\cdot98=49\left(g\right)\)

   \(\Rightarrow m_{ddH_2SO_4}=\dfrac{49}{15}\cdot100=326,67\left(g\right)\)

c) \(m_{BaSO_4}=0,5\cdot233=116,5\left(g\right)\)