Part 2: Chemfig aligning arrows from atom to atom

Question

Having successfully received some help for building up a reaction scheme, another problem occurred:

The Arrow from one Hydrogen atom is not pointing directly to the other Hydrogen atom.

I also want it to be fixed:

\documentclass{article}

\usepackage{chemfig}
\usepackage{amssymb}


\begin{document}


\schemestart
\chemfig[atom sep=32pt]{C([2]-H)([4]-H)(-\charge{90=\|,-90=\|}{O}-@{h1}H)([6,2]-C([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-@{h2}H)([6,2]-C([6,1]-@{c3}H)([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-[0,1]@{h3}H)))}
\arrow(@{c3}--)[-90,1]
\chemfig[atom sep=32pt]{C([2]-@{hh1}H)([4]-H)(-\charge{90=\|,-90=\|}{O}-H)([6,2]-C([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-H)([6,2]-C([6,1]-@{c3}H)([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-[0,1]H)))}
\arrow(@{h1}--){0}[0,0.063]\+ 
\chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]-CH_3)} 
\arrow(@{h3}--){0}[0,0.063]\+
\chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]-CH_3)} 
\arrow(@{h2}--){0}[0,0.063]\+
\chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]=-[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]-CH_3)} 
\schemestop

\end{document}

Before it was fixed:

Answer 1

Easy. Add an "invisible" bond (-[4,1.1,,,draw=none]) to the hydrogen on the left in the bottom molecule. This will equal the horizontal size of this molecule, and the hydrogen on top will be in the center of the molecule.

\documentclass{article}

\usepackage{chemfig}
\usepackage{amssymb}


\begin{document}
    
    
    \schemestart
    \chemfig[atom sep=32pt]{C([2]-H)([4]-H)(-\charge{90=\|,-90=\|}{O}-@{h1}H)([6,2]-C([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-@{h2}H)([6,2]-C([6,1]-@{c3}H)([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-[0,1]@{h3}H)))}
    \arrow(@{c3}--)[-90,1]
    \chemfig[atom sep=32pt]{C([2]-@{hh1}H)([4]-H-[4,1.1,,,draw=none])(-\charge{90=\|,-90=\|}{O}-H)([6,2]-C([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-H)([6,2]-C([6,1]-@{c3}H)([4,1]-H)([0,1]-\charge{90=\|,-90=\|}{O}-[0,1]H)))}
    \arrow(@{h1}--){0}[0,0.063]\+ 
    \chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]-CH_3)} 
    \arrow(@{h3}--){0}[0,0.063]\+
    \chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]-CH_3)} 
    \arrow(@{h2}--){0}[0,0.063]\+
    \chemfig[atom sep=24pt]{C([3,1]=O)([5,1]-H)([1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]=-[-1,0.5]--[-1,0.5]--[-1,0.5]--[-1,0.5]-CH_3)} 
    \schemestop
    
\end{document}