\def\clm{\chemfig{\charge{0=\|,90=\|,180=\|,-90=\|,45:3pt=$\scriptstyle\ominus$}{Cl}}} 
\schemestart[][west]
\chemfig{-(-[2])(-[-2])-@{nu}\charge{90=\|,-90=\|}{O}H} \arrow{0}[,0]\+ \clm \arrow{0}[,0]\+ \chemfig{@{el}\charge{180=\",45:3pt=$\scriptstyle\oplus$}{H}} 
\arrow{<=>}
\chemfig{-(-[2])(-[-2])-\charge{90=\|}{O}\charge{45:3pt=$\scriptstyle\oplus$}{H_2}} \arrow{0}[,0]\+ \clm
\schemestop
\chemmove{
	\draw[shorten <=3pt,shorten >=4pt]
		(nu)..controls +(90:20mm) and +(160:10mm)..(el);
	}
	
\schemestart[][west]
\chemfig{-(-[2])(-[-2])-[@{ls}]@{el}\charge{90=\|}{O} @{h2}\charge{45:3pt=$\scriptstyle\oplus$}{H_2}} \arrow{0}[,0]\+ \clm
\arrow{<=>}
\chemfig{-\charge{0:3mm=\"$\scriptstyle\oplus$}{}(-[::40])-[::-40]} \arrow{0}[,0]\+ \chemfig{H_2\charge{45=\|,-45=\|}{O}} \arrow{0}[,0]\+ \clm
\schemestop
\chemmove{
	\draw[shorten <=1pt]
		(ls)..controls +(-90:5mm) and +(-120:5mm)..(el);
	}
	
\schemestart[][west]
\chemfig{-@{el}\charge{0:3mm=\"$\scriptstyle\oplus$}{}(-[::40])-[::-40]} \arrow{0}[,0]\+ \chemfig{H_2\charge{45=\|,-45=\|}{O}} \arrow{0}[,0]\+ \chemfig{@{nu}\charge{0=\|,90=\|,180=\|,-90=\|,45:3pt=$\scriptstyle\ominus$}{Cl}}
\arrow{<=>}
\chemfig{-(-[2])(-[-2])-\charge{0=\|,90=\|,-90=\|}{Cl}} \arrow{0}[,0]\+ \chemfig{H_2\charge{45=\|,-45=\|}{O}}
\schemestop
\chemmove{
	\draw[shorten <=3pt,shorten >=4mm]
		(nu)..controls +(-90:20mm) and +(-30:10mm)..(el);
	}