Consider the following set of reactions,
We start with cyclobutadiene and make it react with chloroform and alkaline KOH at a low temperature to form A.
After the formation of A we heat the container mildly to form B.
B is transferred to a container filled with aqueous KOH, later PCC is added. The container is now mildly heated. This gives us the compound C.
On cooling the reaction mixture the compound C breaks to form D and E. When D and E are heated with diphenylacetylene (separately), we get the same compound X.
When X is heated in presence of Poly Phosphoric Acid, We get the final compound Z.
How many signals appear in compound Z's H-NMR?
Problem 19 in the IChO's preparatory paper.