Question

Na2O + HCl -> NaCl + H2O

Answer 1

Na2O  + HCl→ NaCl  +H2O

Does  the equation  above  satisfy  the law  of mass  conservation   of matter.

No, since  there  are two sodium atoms as  reactants,  but  only   one sodium  atom as a  product.

Explanation

According  to the law of mass conservation  the  number of atoms in the reactant  side  must be equal  to  the   number of atoms in the  product side.

For  this  reason the equation above does  not satisfy the law of mass  conservation  since the  number of sodium  atoms  are  not equal  in both side.