<a href="https://en.wikipedia.org/wiki/Skeletal_structure" class="extiw" title="en:Skeletal structure">Skeletal structures</a> for the <a href="https://en.wikipedia.org/wiki/hydrogenation" class="extiw" title="en:hydrogenation">hydrogenation</a> of <a href="https://en.wikipedia.org/wiki/acetylenedicarboxylic_acid" class="extiw" title="en:acetylenedicarboxylic acid">acetylenedicarboxylic acid</a> using <a href="https://en.wikipedia.org/wiki/Lindlar_catalyst" class="extiw" title="en:Lindlar catalyst">Lindlar catalyst</a>, giving <a href="https://en.wikipedia.org/wiki/maleic_acid" class="extiw" title="en:maleic acid">maleic acid</a> not <a href="https://en.wikipedia.org/wiki/fumaric_acid" class="extiw" title="en:fumaric acid">fumaric acid</a>
<a href="//commons.wikimedia.org/wiki/User:DMacks" title="User:DMacks">DMacks</a> (<a href="//commons.wikimedia.org/wiki/User_talk:DMacks" title="User talk:DMacks"><span class="signature-talk">talk</span></a>)
<span class="int-own-work" lang="en">Own work</span>