a,
A là ankin => $M= 14n-2$
$M= 2,125.32= 68$
=> $14n-2=68$
=> $n= 5$
Vậy CTPT A là $C_5H_8$.
Các CTCT:
$CH \equiv C-CH_2-CH_2-CH_3$ (1)
(pent-1-in)
$CH_3 - C \equiv C - CH_2-CH_3$ (2)
(pent-2-in)
$CH_3-CH(CH_3)-C \equiv CH$ (3)
(3-metylbut-1-in)
b,
Đồng phân (1), (3) tác dụng với $AgNO_3/NH_3$ vì là ank-1-in.
PTHH:
$CH\equiv C-CH_2-CH_2-CH_3+ AgNO_3+NH_3 \rightarrow AgC\equiv C-CH_2-CH_2-CH_3+ NH_4NO_3$
$CH_3-CH(CH_3)-C\equiv CH+ AgNO_3+ NH_3 \rightarrow CH_3-CH(CH_3)-C\equiv CAg + NH_4NO_3$