Nucleophilic Substitution
It should be better to write equations as

$$\ce{RCl +H2O &lt;=&gt; ROH +HCl}$$

$$\ce{Fe^2+ +Zn &lt;=&gt;&gt; Zn^2+ + Fe }$$

with the latter having the equilibrium shifted to far right. 

But is case of high concentration of $\ce{Fe^2+}$ and very low concentration of $\ce{Zn^2+}$, the net reaction would be ongoing leftwards.

If the left side of equation below is smaller than right one, the net reaction in inclined toward iron being replaced by zinc. And vice versa.

$$E^{\circ}_{\ce{Zn/Zn^2+}}+0.0295\log {a_{\ce{Zn^2+}}}=E^{\circ}_{\ce{Fe/Fe^2+}}+0.0295\log {a_{\ce{Fe^2+}}}$$

Note that forward and backward reaction are ongoing simultaneously, having the same rate at the equilibrium.