Question

How many grams of concentrated nitric acid should be used to prepare 250 ml of 2M HNO3? The concentrated acid is 70% HNO3.

a. 157.14 g
b. 178.57 g
c. 200.00 g
d. 225.00 g

Answer 1

To prepare 250 ml of 2M HNO3, 31.5 grams of concentrated nitric acid should be used.

Step-by-step explanation:

To calculate the number of grams of concentrated nitric acid needed to prepare 250 ml of 2M HNO3, we can use the formula:

Mass = Volume x Concentration

First, we need to convert the volume from milliliters to liters:

Volume = 250 ml = 0.25 L

Next, we can use the formula to calculate the mass:

Mass = 0.25 L x 2M = 0.5 moles

Now, we need to convert moles to grams using the molar mass of HNO3:

Molar mass of HNO3 = 1g + 14g + 3(16g) = 63g/mol

Mass = 0.5 moles x 63g/mol = 31.5g

Therefore, the correct answer is 31.5 grams (option d).