Question

what will be the molarity of a solution, which contains 5.85g of NaCl per 500ml?

Answer 1

Molarity = mole / volume

Molecular mass of NaCl = 23 + 35.5
= 58.5
Moles = given mass/molecular mass
= 5.85/58.5
= 0.1
Convert ml into litre
1 litre = 1000ml
1/1000 litre = 1 ml
So, 500ml = 1/2 litre = 0.5 litre

Molarity = 0.1/0.5
= 1/5
=0.2M

Answer 2

0.2 mol L^-1

Given:

Quantity of NaCl per 500 ml = 5.85 grams

Converting 500 ml to litre by dividing by 1000:

= 0.5 Litre

To Find:

Molarity of the solution

Formula used to find the molarity of a solution:

M = No of moles of solute / Volume of solution in Litres

Calculating the Molar Mass of NaCl:

= 1 x 23 + 1 x 35.5

= 23 + 35.5

= 58.5

Calculating the moles of solute in the solution:

= Weight / Molar Mass

= 5.85 / 58.5

= 0.1 mol

Calculating the molarity of the solution by substituting the values we know into the formula mentioned above:

M = No of moles of solute / Volume of solution in Litres

= 0.1 / 0.5

= = 0.2 mol L^-1

Therefore, 0.2 mol L^-1 will be the molarity of the solution which contains 5.85 grams of NaCl per 500 ml.