What would be the molar concentration of a 0.85% solution of sodium hypochlorite? (assume the density of solution to be 1.0 g/ml.) ?

0.11 M

I am assuming that the 0.85% is by weight. So let's start with determining the molar mass of sodium hypochlorite (NaClO).

Atomic weight sodium = 22.989769

Atomic weight chlorine = 35.453

Atomic weight oxygen = 15.999

Molar mass NaClO = 22.989769 + 35.453 + 15.999 = 74.442 g/mol

Now 1 liter of the solution will contain 1000 g * 0.0085 = 8.5 g.

Moles NaClO = 8.5 g / 74.442 g/mol = 0.114182854 mol

And since molarity is defined as moles per liter, the result (rounded to 2 significant digits) is 0.11 M