Mass Percentage and Density of Solution JEE Chemistry

 

❓ Question

Concentrated nitric acid is labeled as 75% by mass. The volume (in mL) of the solution containing 30 g of $HNO_3$ is:

Given: Density of nitric acid solution = 1.25 g mL⁻¹

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✍️ Solution

Given,

• Mass percentage of $HNO_3 = 75\%$
  
• Mass of pure $HNO_3 = 30$
  

Let the mass of the solution be $m$ g.

Using mass percentage,

$$\frac{\text{Mass of }HNO_3}{\text{Mass of solution}}\times100=75$$
$$\frac{30}{m}\times100=75$$
$$m=\frac{30\times100}{75}=40\text{ g}$$

Now,

$$\text{Density}=\frac{\text{Mass}}{\text{Volume}}$$
$$\text{Volume}=\frac{\text{Mass}}{\text{Density}}$$
$$=\frac{40}{1.25}=32\text{ mL}$$

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✅ Final Answer

$$\boxed{32\ \text{mL}}$$