Question

concentrated HNO3 used in laboratary work is 68% by mass in aqueous solution.find out molarity if density of solution is 1.504 gm/cm^3​

Answer 1

Explanation:

concentrated HNO3 used in laboratary work is 68% by mass in aqueous solution.find out molarity if density of solution is 1.504 gm/cm^3

Answer 2

Solution :-

68 % m /m means 68 g of HNO3 (solute )in  100 g solution

• Solvent (H2O) = 100 - 68 = 32 g

• Density of solution = 1.504 g /cm³

Step I : Find moles of HNO3

• Mass of HNO3 (W)= 68 g

• Molar mass of HNO3 (M)= H + N + 3 (O) = 1 + 14 + 48 = 63 g

We know that ,

⇒ n = W / M

⇒ n = 68 / 63

⇒ n = 1.07

Step II : Volume of solution

• Mass of solution(m) = 100 g

• Density (d)= 1.504 g / cm³

we know that ,

⇒ d = m / v

⇒ v = m / d

⇒ v = 100 / 1.504

⇒ v = 66.4 cm³ / 66.4 mL

⇒ v = 0.066 L

Step III : Molarity

⇒ M = n / v

⇒ M = 1.07 / 0.066

⇒ M = 16.21 mol / L

The molarity of the solution is 16.21 M