Question

How many grams of concentrated nitric acid solution should be used to prepare 250 ml of 2.0 m agno3 the concentrated acid is 70%?

Answer 1

Answer:

No. of moles = (250×1000)/2

= 0.5 moles

No. of moles = molarity × volume

Requird mass of HNO3 = 0.5 × 63

= 31.5 gm

70 gm of HNO3 are present in 100 gm of solution,

So 1 gm will be present in 100/70 gm of solution.

31.5 gm be present in (100/70)× 31.5 gm of solution

= 45 gm

Answer 2

Explanation:

The required number of moles=( 250/1000)×2

=0.5 moles

(no. of moles=molarity × volume)

so,required mass of HNO3=0.5×63

=31.5 grams

(given mass=no. of moles × molar mass)

Given,

70 grams of HNO3 are present in 100 grams of the solution

so,1 gram will be present in 100/70 grams of solution

hence 31.5 grams will be present in (100/70)×31.5 grams of solution.

so amount of concentrated nitric acid solution used is 45 grams.