Question

calculate the molarity of sodium hydroxide solution containing 25 g/l of the solution​

Answer 1

Answer:

molality=

kilograms of solvent

moles of solute

moles of NaOH=

Mass of NaOH

Weight of NaOH

=

40

25

=

8

5

=0.625

kilograms of H

2

O=

1000

Weight of H

2

O

=

1000

100

=0.1

∴molality=

kilograms of solvent

moles of solute

=

0.1

0.625

=6.25m

Hence, the correct answer is 6.25.

Answer 2

Given:

25 g/l of sodium hydroxide solution

To Find: Molarity of sodium hydroxide solution

Solution:

Since the solution of sodium hydroxide is 25 g/l, it means 25 g of sodium hydroxide is present in 1 litre or 1000 ml of solution.

Therefore, the number of moles of sodium hydroxide can be given as:

$\[No.\,of\,moles = \frac{{Mass}}{{Molar\,mass}}\]$

$\[No.\,of\,moles = \frac{{25\,g}}{{40}}\]$

$\[No.\,of\,moles = 0.625\]$

Thus, the molarity of sodium hydroxide solution can be given as:

$\[Molarity = \frac{{No.\,of\,moles}}{{Volume\,of\,solution}}\]$

$\[Molarity = \frac{{0.625}}{{1\,l}}\]$

$\[Molarity = 0.625\,mol/l\]$

Hence, the molarity of the solution is $\[0.625\,mol/l\]$.