Buta-1,3-đien : $CH_2=CH-CH=CH_2$

$CH_2=CH-CH=CH_2 + 2H_2 \xrightarrow{t^o,Ni} CH_3-CH_2-CH_2-CH_3$

a)

$2Ba + O_2 \xrightarrow{t^o} 2BaO$
$BaO + H_2O \to Ba(OH)_2$
$Ba(OH)_2 + H_2SO_4 \to BaSO_4 + 2H_2O$

b)

$2Ca + O_2 \xrightarrow{t^o} 2CaO$
$CaO + H_2O \to Ca(OH)_2$
c)

$C + O_2 \xrightarrow{t^o} CO_2$
$CO_2 + H_2O \rightleftharpoons H_2CO_3$

$C_2H_4 + Br_2 \to C_2H_4Br_2$

Ta có : 

$m_{C_2H_4} = m_{dd\ tăng} = 3(gam)$

$\Rightarrow n_{C_2H_4} = \dfrac{3}{28}(mol)$

$\Rightarrow n_{C_2H_6} = 0,25 - \dfrac{3}{28} = \dfrac{1}{7}(mol)$

$\%V_{C_2H_4} = \dfrac{ \dfrac{3}{28} }{0,25}.100\% = 42,9\%$

$\%V_{C_2H_6} = 100\% - 42,9\% = 57,1\%$

$\%m_{C_2H_4} = \dfrac{3}{3 + \dfrac{1}{7}.30}.100\% = 41,2\%$

$\%m_{C_2H_6} = 100\% - 41,2\% = 58,8\%$

$C_2H_4 + Br_2 \to C_2H_4Br_2$

Ta có : 

$m_{C_2H_4} = m_{dd\ tăng} = 3(gam)$

$\Rightarrow n_{C_2H_4} = \dfrac{3}{28}(mol)$

$\Rightarrow n_{C_2H_6} = 0,25 - \dfrac{3}{28} = \dfrac{1}{7}(mol)$

$\%V_{C_2H_4} = \dfrac{ \dfrac{3}{28} }{0,25}.100\% = 42,9\%4

$\%V_{C_2H_6} = 100\% - 42,9\% = 57,1\%$

$\%m_{C_2H_4} = \dfrac{3}{3 + \dfrac{1}{7}.30}.100\% = 41,2\%$

$\%m_{C_2H_6} = 100\% - 41,2\% = 58,8\%$

$C_2H_4 + Br_2 \to C_2H_4Br_2$
Theo PTHH : 

$n_{C_2H_4} = n_{Br_2} = 0,1.2 = 0,2(mol)$
$\%m_{C_2H_4} = \dfrac{0,2.28}{10}.100\% = 56\%$

$\%m_{CH_4} = 100\% - 56\% = 44\%$