Consider the reaction below.

mg(s) + 2hcl(aq) --> h2(g) + mgcl2(aq)

what is the most likely effect of an increase in pressure on this reaction?

the reactant surface area increases.
the reaction rate decreases.
the reaction is not affected at all.
the reaction stops completely.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.