M,CO= 28g/mol
M,H2=2g/mol
M,mediu= (28+2)/2---> 15g/mol
d= M,hidroc/M,mediu; 4,533=M/15--->M= 68g/mol--> pentina
A. CH≡ C-CH2-CH2-CH3 1 PENTINA, are 2 atC cu hibridizare sp2
C .CH≡C-CH(CH3)-CH3 3METIL 1PENTINA(izomer de catena cu A) nu are atom C secundar
B CH3-C≡C-CH2-CH3 2 PENTINA-izomer de pozitie.