First of all we need no.of moles of 100g sodium chromate
Molar mass of sodium chromate = 161.97g/mol
No of mole =mass in gram/molar
=100/161.97
= 0.617mol
Now to find molarity apply formula
Molarity= moles of solvent/solution in liter
= 0.617/5
=0.1234M solution of sodium chromate