Question

30. how many grams of boric acid, b(oh)3 (fm 61.83), should be used to make 2.00 l of 0.050 0 m solution? what kind of fl ask is used to prepare this solution?

Answer 1

Mass = 6.183 g

Solution:

Step 1: Calculate number of moles of Boric acid using following formula,

Molarity = Moles ÷ Volume

Solving for Moles,

Moles = Molarity × Volume

Putting Values,

Moles = 0.05 mol.L⁻¹ × 2.0 L

Moles = 0.1 mol

Step 2: Calculate Mass of Boric Acid using following formula,

Moles = Mass ÷ M.mass

Solving for Mass,

Mass = Moles × M.mass

Putting values,

Mass = 0.1 mol × 61.83 g.mol⁻¹

Mass = 6.183 g

Flask used to prepare this solution is called as Volumetric flask. Take 2 L volumetric flask, add 6.183 g of Boric acid and fill it to the mark with distilled water.