Question

How many grams of NaCl must be added to water to create 5.0 L of a 0.157 M normal saline solution?

a. 7.5 g KCl
b. 10.2 g NaCl
c. 14.8 g NaCl
d. 20.5 g KCl

Answer 1

To create a 0.157 M normal saline solution in 5.0 L of water, you would need to add 45.84 g NaCl.

Step-by-step explanation:

To determine the grams of NaCl needed to create a 0.157 M solution in 5.0 L of water, we can use the formula:

Molarity (M) = moles of solute / liters of solution.

Since the molar mass of NaCl is 58.44 g/mol, we can rearrange the formula to solve for grams:

moles of solute = Molarity * liters of solution

grams = moles of solute * molar mass

Substituting the given values, we get:

moles of NaCl = 0.157 M * 5.0 L = 0.785 moles

grams of NaCl = 0.785 moles * 58.44 g/mol = 45.84 g

Therefore, the correct answer is c. 45.84 g NaCl.