Question

A) An aqueous solution of methyl alcohol is made by transfering 2.39 mL of liquid methyl alcohol to a 100. mL volumetric flask, and then adding enough water to fill the flask to the mark. What is the volume/volume percentage of methyl alcohol in the solution?

B) An aqueous solution of acetone is made by transfering 7.17 mL of liquid acetone to a 100. mL volumetric flask, and then adding enough water to fill the flask to the mark. What is the volume/volume percentage of acetone in the solution?

C) How many mL of propyl alcohol are required to make a 5.57% (v/v) aqueous solution in a 100. mL volumetric flask?

Answer 1

A)

Volume of methyl alcohol taken = 2.39 mL

Total volume of solution i.e. methyl alcohol + Water = 100.0 mL

(v/v)% methyl alcohol in water = (Volume of methyl alcohol / Total volume of solution) * 100

                                               = (2.39 mL / 100.0 mL) * 100

                                               = 2.39 %

(v/v)% methyl alcohol in water = 2.39 %

B)

Volume of Acetone = 7.17 mL

Volume of solution i.e. Acetone+Water = 100.0 mL

(v/v)% Acetone in water = (7.17 mL / 100.0 mL) * 100 = 7.17 %.

(v/v)% Acetone in water = 7.17 %

C)

Volume propyl alcohol = ?

Volume of solution i.e. propyl alcohol + water = 100.0 mL

(v/v) % propyl alcohol in water = 5.57 %

Now,

(v/v) % propyl alcohol in water = (volume of propyl alcohol / volume of solution) * 100

5.57 = (Volume of propyl alcohol / 100.0 mL) * 100

Volume of propyl alcohol = 5.57 mL.

Preparation: Take 5.57 mL propyl alcohol in 100.0 mL volumetric flask and add enough distilled water to make it upto 100.0 mL total volume.

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