10.8 g of alkene reacted completely with 14.6 g of HCL to find the formula for alkyne.

Given:

m (CnH2n) = 10.8 g

m (HCl) = 14.6 g

CnH2n -?

CnH2n + HCl = CnH2n + 1Cl

n (HCl) = m / Mr = 14.6 / 36.5 = 0.4 (mol) is the amount of chloride acid;

n (CnH2n) = n (HCl) = 0.4 (mol);

Mr (CnH2n) = m (CnH2n) / n = 10.8 / 0.4 = 27 (g / mol);

Let’s make an equation in order to find out n – the number of carbon atoms in an alkene molecule:

12 * n + 2 * n * 1 = 27

14 * n = 27

n = 2, then ethylene reacted – C2H4.