a) PTHH:
$C_2H_2+2Br_2→C_2H_2Br_4$
$CH_4$ không phản ứng với dung dịch Brom.
b) $n_{Br_2}=\dfrac{16}{160}=0,1(mol)$
$n_{C_2H_2}=\dfrac{1}{2}n_{Br_2}=\dfrac{1}{2}×0,1=0,05(mol)$
Mà ta lại có: $n_{\text{hh khí}}=\dfrac{4,48}{22,4}=0,2(mol)$ → $n_{CH_4}=0,2-0,05=0,15(mol)$
⇒ %$V_{C_2H_2}=\dfrac{0,05}{0,2}×100$% $=$ $25$%
⇒ %$V_{CH_4}=100$% $-$ $25$% $=$ $75$%
c) $CH_4+2O_2\buildrel{{t^o}}\over\longrightarrow CO_2+2H_2O$
$2C_2H_2+5O_2\buildrel{{t^o}}\over\longrightarrow 4CO_2+2H_2O$
Ta có:
$n_{O_2}=2n_{CH_4}=2×0,15=0,3(mol)$
$n_{O_2}=\dfrac{5}{2}n_{C_2H_2}=\dfrac{5}{2}×0,05=0,125(mol)$
⇒ $V_{O_2}=22,4×(0,3+0,125)=9,52(l)$