Đáp án:

$31.C_{5}H_{12} \xrightarrow{\text{$t^{o} ,crackinh$}} CH_{4} + C_{4}H_{8}$

$32.C_{5}H_{12} \xrightarrow{\text{$t^{o} ,crackinh$}} C_{2}H_{6} + C_{3}H_{6}$

$33.C_{5}H_{12} \xrightarrow{\text{$t^{o} ,crackinh $}} C_{3}H_{8} + C_{2}H_{4}$

$34.C_{4}H_{10} \xrightarrow{\text{$t^{o} , xt$ }} C_{4}H_{8} + H_{2} $

$35.C_{3}H_{8} \xrightarrow{\text{$t^{o} , xt$ }} C_{3}H_{6} + H_{2} $

$36.C_{5}H_{12} \xrightarrow{\text{$t^{o} , xt$ }}C_{5}H_{10} + H_{2} $

$37.CH_{3}COONa + NaOH_{(r)} \xrightarrow{\text{$CaO,t^{o}$ }} CH_{4} + Na_{2}CO_{3}$ 

$38.C_{2}H_{5}COONa + NaOH_{(r)} \xrightarrow{\text{$CaO,t^{o}$ }} C_{2}H_{6} + Na_{2}CO_{3}$ 

$39.C_{3}H_{7}COONa+ NaOH_{(r)} \xrightarrow{\text{$CaO,t^{o}$ }} C_{3}H_{8} + Na_{2}CO_{3}$ 

$40.2CH_{4} \xrightarrow{\text{$1500^{o}C , làm lạnh nhanh$ }} C_{2}H_{2} + 3H_{2} $

$41.C_{n}H_{2n+2}  + \frac{3n+1}{2}O_{2} → nCO_{2}  + (n+1)H_{2}O$ 

$42.C_{3}H_{8}  + 5O_{2} → 3CO_{2}  + 4H_{2}O$ 

$43.C_{5}H_{12}  + 8O_{2} → 5CO_{2}  + 6H_{2}O$