Question

calculate the molarity of solution when 1.23 gram sodium hydroxide dissolved in water to make 100cm³ of solution?​

Answer 1

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

Molarity=\frac{n\times 1000}{V_s}Molarity=Vsn×1000

where,

n = moles of solute

V_sVs = volume of solution in  ml = 100cm^3=100ml100cm3=100ml1cm63=1ml1cm63=1ml

moles of solute =\frac{\text {given mass}}{\text {molar mass}}=\frac{2.46g}{40g/mol}=0.062molesmolar massgiven mass=40g/mol2.46g=0.062moles

Now put all the given values in the formula of molarity, we get

Molality=\frac{0.062\times 1000}{100ml}=0.62mole/LMolality=100ml0.062×1000=0.62mole/L

Therefore, the molarity of solution is 0.62 M

Answer 2

GIVEN:

• Mass of solute = 1.23g
• Volume of solution =100cm³=100×10^-3 L = 0.1 L

TO FIND:

• Molarity

SOLUTION

moles of solute

= mass of solute/molar mass

= 1.23/40

= 0.03 moles

Molarity

= moles of solute/ volume of soln (L)

=0.03/0.1

=0.3

Molarity = 0.3 M