160g..........x
2NaOH+H2S-->Na2S+2H2O
2×30.........34
[tex]c = \frac{md}{ms} \times 100 \\ md = \frac{c \times ms}{100} \\ md = \frac{40 \times 400}{100} = 160g[/tex]
M(NaOH)=A(Na)+A(O)+A(H)
M(NaOH)=23+16+1=30
M(H2S)=2Ah+As=2+32=34
[tex]x = \frac{160 \times 34}{2 \times 30} = 90.66g[/tex]
[tex]c = \frac{md}{ms} \times 100 \\ ms = \frac{md \times 100}{c} \\ ms = \frac{90.66 \times 100}{34} = 266.64 \: g \: [/tex]
