<p>what would be the reactants when u react oxirane and ethylene glycol saturated in H+ solution?</p>
<p>Is this a trick question or a typo? You said it yourself - the reactants are oxirane and ethylene glycol.</p>
<p>To be more precise, is the H+ a necessary catalyst or does it take part in the reaction?</p>
<p>I did it out on paper. H+ is a catalyst. Specifically (spoilers follow):</p>
<ol>
<li>The expoxide grabs a proton (though there is heavy ring strain, the glycol isn’t a good enough nucleophile to attack). </li>
<li>Now the glycol attacks. After the attack, the glycol loses a proton (the attacking hydroxyl has a positive charge otherwise). </li>
<li>One end of the new molecule (ie. one of the hydroxyls) grabs a proton. </li>
<li>The other end attacks intramolecularly SN2 style. releasing water, and forming a 6 membered cyclic molecule.</li>
<li>The cyclic molecule loses a proton (again otherwise you have a + on an oxygen). </li>
</ol>
<p>If you tally protons, there is no net change in their concentration. I’m not perfect, but this problem wasn’t too hard (ie. small chance I messed up somewhere). Rather fun actually. PM if it helped (I don’t check/post often).</p>