The percentage ( by weight ) of sodium hydroxide in a 1.25 molal NaOH solution is

Options

A. `4.76%`
B. `1.25%`
C. `5%`
D. `40%`

Answer

A

Explanation

1.25 molal NaOH solution means, 1.25 moles of NaOH are present in 1000 g of water
`:.` Weight of NaOH `=1.25xx40=50g`
Weight of solution `= 1000+50=1050g `
% ( by weight ) of NaOH `=("wt. of solute ")/("wt. of solution ")xx100=(50)/(1050) xx 100=4.76%`