Question

Calculate the molarity of a solution containing 8g of NaOH in 500mL of water

Answer 1

Mole of naoh =8/40= 0.2 mol
Molarity= 0.2×1000/500= 0.4mol/l

Answer 2

Answer : The molarity of a solution is 0.4 mole/L.

Solution : Given,

Volume of solution = 500 ml

Mass of NaOH = 8 g

Molar mass of NaOH = 40 g/mole

Molarity : It is defined as the number of moles of solute present in one liter of a solution.

Formula used :

$Molarity=\frac{w_{NaOH}\times 1000}{M_{NaOH}\times V_{solution(L)}}$

where,

${w_{NaOH}$ = mass of NaOH

${M_{NaOH}$ = molar mass of NaOH

V = volume of solution in liter

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

$Molarity=\frac{8g\times 1000}{40g/mole\times 500L}=0.4mole/L$

Therefore, the molarity of a solution is 0.4 mole/L.