1. If the density of methanol is 0.793 kg L-1, what is the volume needed for making 2.5 L of its 0.25 M solution ?

**Please answer in brief with explanation to it...**

The molarity of a solution is defined as = number of moles of solute/ Volume of solution (in litres) = (mass of solute/ molar mass of solute)X (1/ Volume of solution (in litres)

Let x g of methanol (molar mass = 32g) be required to prepare a 0.25 Molar solution of methanol.

Therefore we have 0.25 = (x/32) X (1/2.5)

x = 20g = 0.02 Kg

Now density = Mass/ Volume

We are given that the density of methanol is 0.793 KgL^{-1}.

Therefore, Volume = Mass/ Density = 0.02/0.793 = 0.025 Litres

Therefore 0.025 Litres of methanol would be required.

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