a solution is made by dissolving sodium chloride in water and its concenteration is expressed as 0.09percentage by mass.caculate no.of moles and no.of molecules

If the solution is 100g.

Mass of solute i.e.NaCl = 0.9 g

Molar mass of NaCl =58.4 g

Number of moles of 0.9 g NaCl = 0.9/58.4 = 0.0154 mole

Number of molecules in 0.0154 mole =0.0154  x 6.023 x 10²³ =  9.3x10²¹