Question

Hấp thụ 672 ml H2S(đktc) vào V ml dd NaOH 0,1M thu được dd X. Xác định khối lượng muối (g) thu được khi 

 a. V=750 ml 

A. 4,2  B. 2,925  C. 1,68  D. 2,34 

b. V=420 ml 

A. 1,344  B. 1,944  C. 1,900  D. 1,672 

Answer 1

\(n_{H_2S}=\dfrac{0.672}{22.4}=0.03\left(mol\right)\)

\(a.\)

\(n_{NaOH}=0.75\cdot0.1=0.075\left(mol\right)\)

\(T=\dfrac{0.075}{0.03}=2.5>2\)

=> Tạo muối trung hòa

\(2NaOH+H_2S\rightarrow Na_2S+H_2O\)

\(0.06............0.03.........0.03\)

\(m_{Na_2S}=0.03\cdot78=2.34\left(g\right)\)

Answer 2

\(b.\)

\(n_{NaOH}=0.42\cdot0.1=0.042\left(mol\right)\)

\(T=\dfrac{0.042}{0.03}=1.4\)

=> Tạo 2 muối

\(n_{Na_2S}=a\left(mol\right),n_{NaHS}=b\left(mol\right)\)

\(\left\{{}\begin{matrix}2a+b=0.042\\a+b=0.03\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}a=0.012\\b=0.018\end{matrix}\right.\)

\(m_{Muối}=0.012\cdot78+0.018\cdot56=1.944\left(g\right)\)