NEET Questions Solved


How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3? The concentrated acid is 70% HNO3.

(a) 45.0 g conc. HNO3

(b) 90.0 g conc. HNO3

(c) 70.0 g conc. HNO3

(d) 54.0 g conc. HNO3

(a) Given, molarity of solution=2

Volume of solution = 250mL=250/1000=1/4L

Molar mass of HNO3 = 1+14+3x16=63g mol-1

Molarity = weight of HNO3Molecular mass  of HNO3×volume of solution(L)

Weight of  HNO3 = molarity x molecular massx volume(L) = 2x63x1/4g=31.5g

It is the weight of 100%  HNO3

But the given acid is 70% HNO3

Its weight = 31.5x100/70g=45g

 

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