Consider hydrocarbon molecules with the formula C4Hx in which the four carbons form a linear chain. Sketch the structure and find the value of x if there are (a) no π bonds; (b) exactly one π bond; (c) two π bonds, each on a different C—C pair; (d) two π bonds on the same C—C pair; (e) three π bonds, each on different C—C pairs; and (f) three π bonds, two on one C—C pair and one on a different C—C pair.