Question

The molarity of a naoh solution by dissolving 4 g of it in 250 ml water i

Answer 1

Molarity = moles divided by volume of solution in litres

moles = weight divided by molar mass

hence we get , weight or mass given

molar mass X volume in litres

as volume is given in ml we will divide it by 1000 to convert it into litre

hence the formula we get is ; weight or mass (given) X 1000

molar mass X volume in ml

according to your question = molar mass of NaOH = (Na) 23+ (O) 16 + (H) 1=40

= 4 X 1000 / 40 X 250

= 2/5 = 0.4 mol L^-1

hope it helps ...............