Question

The percentage by weight of sodium hydroxide in a 1.25 molal naoh solution is ?

Answer 1

Hi,

Below is the answer.

1.25 of molal NAOH solution means 1.25 moles of NAOH in 1kg of water

Mass of NAOH= Number of Moles into Molar Mass

=1.25*40

=50g

Now, Mass of Water= 1000g

Hence, Mass of Water+ Mass of NAOH= Mass of Solution

=1000g + 50g = 1050g

Now percentage of molar solution

=mass of NAOH /mass of solution * 100

=50g/1050g * 100

=94.24% ans

I hope the above solution helped.

Answer 2

correct answer is 4.74