Question

A1 L sample from Tempe Town lake has a pH of 3. 57. Exhaust from cars on nearby highways

often mixes with rain to form HNO3. Use this information to answer the following questions.

1. What is the concentration of H+ ions in the sample?

2. If it took 80 ml of 1 M NaOH to neutralize 250 ml of the acidic solution, what is the

molarity of HNO3 in the sample?

3. How many moles of HNO3 are in the

solution?

Answer 1

see explanations

Step-by-step explanation:

1. pH = -log [H+]

so [H+] = 10^(-pH) = 10^(-3.57) = 2.7 x 10^(-4) M

2. neutralize implies mol acid = mol base

so [HNO3] = (1 M) * (0.080 L) / (0.250 L) = 0.32 M HNO3

3. mol HNO3 = molarity of HNO3 * volume of HNO3

= 0.32 M HNO3 * 0.250 L HNO3 = 0.080 mol HNO3