Chem. Question! Which would be the correct asnwer?

When will le chatelier's principle come into effect? at the beginning of a reaction, when there are only reactants when a reaction has reached chemical equilibrium when a catalyst is added to a reaction mixture when a reaction is occurring but not yet at equilibrium

Smog is the term used to describe the combination of fog and smoke

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.