Between the position isomer and chain isomer of but -1- ene, which one exhibits geometrical isomerism and why ?

Explanation

Position isomer of but-1-ene is but-2-ene
`(CH_3CH=CHCH_3)` and chain isomer of but-1-ene is 2-methylpropene `[(CH_3)_2C=CH_2]`. In a molecule of but 2-ene , different groups are attached to the C-atom which is linked to the double bond. So, but-2-ene exhibits geometrical isomerism. On the other hand , in a molecule of 2-methylpropene, two similar atoms (H-atom ) are attached to the C-atom linked to the duoble bond. So, 2-methylpropene ,does not exhibit geometrical isomerism.