In the reaction of magnesium metal with hydrochloric acid, how do you determine when the magnesium metal has reacted completely? a. All of the water has evaporated.
b. The magnesium metal is gone.
c. The dilute HCl is gone.
d. Gas bubbles are no longer produced.

what is the question here. i think you messed up.

може ли да зареждате повече информация, моля

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.