Question

what weight of sodium hydroxide should to be dissolved to prepare 250ml of 0.2m solution​

Answer 1

Answer:

Weight of sodium hydroxide required to prepare 250ml of 0.2m solution = 2 gram

Explanation:

As molarity = number of moles / liter

Thus to prepare 0.2 molar solution the number of moles required = 0.2 / liter

Now the volume of solution = 250ml = 0.25 liter = 1/4 liter

Thus the number of moles required

$n = 0.2( \frac{1}{4} ) = 0.05mol$

1mol of NaOH = 40g

Hence

0.05 mol of NaOH = 0.05 × 40 = 2 gram