Question

calculate the mass of KOH required to make 250 ml 0.2 m solution​

Answer 1

Correct question :-

Calculate the mass of KOH required to make 250mL of 0.2 M solution.

Answer:-

2.8g

Explanation :-

Let the required mass of KOH be 'x' g.

• Molar mass of Potassium (K) = 39g/mol

• Molar mass of Oxygen (O) = 16g/mol

• Molar mass of Hydrogen (H) = 1g/mol

Hence, molar mass of KOH :-

= 39+17+1

= 56g/mol

Number of moles in x gram KOH :-

= Given Mass/Molar mass

= x/56 mole

Now, let's convert the volumw of the solution from mL to L .

=> 250mL = 250(0.001) = 0.25L

Molarity of a solution :-

= Moles of solute/Liters of solution

=> [x/56]/0.25 = 0.2

=> x/[56×0.25] = 0.2

=> x/14 = 0.2

=> x = 14(0.2)

=> x = 2.8g

Thus, the required mass of KOH

is 2.8g .