A solution containing 10 g per dm3 of urea (molecular mass = 60 g mol$-$1) is isotonic with a 5% solution of a nonvolatile solute is

Question

A solution containing 10 g per dm³ of urea (molecular mass = 60 g mol^$-$1) is isotonic with a 5% solution of a nonvolatile solute is

200 g mol^$-$1