When Ag+ is combined with Na2CO3, the substances formed are Ag2CO3 and Na+. In this case, Ag performs single substitution over the element Na to form another set of substances. There are other types of reactions like double displacement, decomposition, etc.
Molality=mol/kg
342/171
=2m
Hope this helped :)
The two components of a solution are solvent and solute.
A solution is a homogenous mixture, stable, and the particles are very small.