Question

In what ratio should 6.5N HNO3 be diluted with water to get 3.5N HNO3

Answer 1

Answer:

Suppose we have 100ml stock solution of 6.5N HNO3. From this we intend to dilute to 3.5N of 100ml again.

then, we know that,

N1V1 = N2V2

i.e. 6.5 x V1 = 3.5 x 100

as we don't know how much from the stock should be taken to dilute to final concentration of 3.5N, V1 is to be calculated. V2 is final volume after dilution.

So, V1 = 53.84 ml

So, for final volume of 100ml we need to take 53.84ml from stock and add (100-53.84)ml = 46.16ml water to make a final volume of 100ml 3.5N

Hence ratio of 6.5N HNO3 to water is 53.84/46.16 i.e. approx 27:23

Explanation:

27 parts HNO3 and 23 parts water will give 0.5384 x 6.5 approx 3.5 which our final concentration.