Question

valancy of carbon in alkane and alkine

Answer 1

valency of carbon in alkane is 4
while valancy of copper in alkine is 1

Answer 2

Valency of carbon atom is four. In alkanes carbon form single covalent bond with other carbon atom and with hydrogen atom.for example in ethane CH2CH3 both of carbon atom satisfy it's four valancy by forming single covalent bond with hydrogen atom and also with itself.