Question

What is the volume needed to make 4.2M solution using 6.5 mol NaCl?

Answer 1

Molarity is defined as the number of moles of solute in volume of 1 L solution.
Molarity of NaCl is 4.2 M
the number of NaCl moles present is 6.5 mol
the volume of 4.2 moles is dissolved in 1 L solution
therefore volume required for 6.5 mol is - 6.5 mol / 4.2 mol/L = 1.5 L
therefore volume required is 1.5 L

Answer 2

Molarity is given as,

Molarity = Moles / Volume of Solution ---- (1)

Given Data:
Molarity = 4.2 mol.dm⁻³

Moles = 6.5 mol

To Find:
Volume = ?

Solution:
Solving Eq. 1 for Volume,

Volume = Moles ÷ Molarity
Putting Values,
Volume = 6.5 mol ÷ 4.2 mol.dm⁻³ \

Volume = 1.54 dm⁻³ ∴ 1 dm³ = 1 L