3 is correct because the .1 moles of the NO3 will be better option to decrease the solubility of the Silver Nitrate.
I believe the correct answer from the choices listed above is the last option. The term that would best describe the <span>role of hydrogen gas in the formation of a water molecule would be a reactant. Water has a formula of H2O where it contains water so it should be that hydrogen is a reactant. </span>
