Hydrogen combines with chlorine to form HCl. It also combines with sodium to form NaH. If sodium and chlorine combine with each other, the ratio of their masses will be 

 Mass ratio of H:Cl=1:35.5 in HCl and Na: H=23:1 in NaH.
 According to law of constant proportion compounds always contains its elements in a fixed ratio by mass.
So, for 1gm of H we are having 35.5gm Cl and 23gm Na.
Hence, the ratio Na: Cl=23:35.5.