Calculates the molarity and normality of a solution containing `0.5` g of `NaOH` dissolved in `500 ml`. solution-

Options

A. 0.0025 M, 0.025 N
B. 0.025 M, 0.025 N
C. 0.25 M, 0.25 N
D. 0.025 M, 0.0025 N

Answer

B

Explanation

Wt. of NaOH dissolved = 0.5 gm
Vol. of NaOH solution = 500 ml
Calculation of molarity :
0.5 g of NaOH = `0.5/40` moles of NaOH
[ Mol. wt of NaOH = 40] = 0.0125 moles
Thus 500 ml of the solution contain NaOH = 0.0125 moles
`:.` 1000 ml of the solution contain
`=0.0125/500xx1000=0.025M`
Hence molarity of the solution = 0.025 M
Calculation of normality :
Since NaOH is monoacidic ,
Eq. wt. of NaOH = Mol. wt. of NaOH = 40
`:.`0.5 gm of NaOH = `0.5/40` gm equivalents
= 0.0125 gm equivalents
Thus 500 ml of the solution contain NaOH = 0.0125 gm equ
`:.` 1000 ml of the solution contain
`=0.0125/500xx1000=0.025`
Hence normality of the solution = 0.025 N