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In a titration, a few drops of an indicator are added to a flask containing 35.0 milliiters of HNO3(aq) of unknown concentration. After 30.0 millliters of 0.15 M NaOH(aq) solution is slowly added o the flask, the indicator changes color, showing the acid is neutralized. Which choice is a correct numerical setup for calculating the concentration of the HNO3(aq) solution

2 Answers

5 votes

Final answer:

The concentration of the HNO3(aq) solution can be calculated by using the volume and concentration of NaOH solution to find the moles of NaOH, which are equal to the moles of HNO3 due to the 1:1 stoichiometry of the reaction. The concentration of HNO3 is then found by dividing the moles of HNO3 by the volume of HNO3 in liters.

Step-by-step explanation:

To calculate the concentration of the HNO3(aq) solution, you can set up the calculation based on the neutralization reaction between HNO3 and NaOH. The balanced chemical equation for this reaction is HNO3(aq) + NaOH(aq) → NaNO3(aq) + H2O(l). Since the stoichiometry between the acid and the base is 1:1, we can use the volume and the molarity of NaOH to find the moles of NaOH, which will be equal to the moles of HNO3 due to the 1:1 ratio.

The correct numerical setup for calculating the concentration of the HNO3(aq) solution is:

(Volume of NaOH) × (Molarity of NaOH) = Moles of NaOH = Moles of HNO3
(Concentration of HNO3) = (Moles of HNO3) / (Volume of HNO3)

In this case, it would look like:

0.030 L × 0.15 M = x moles of HNO3
x moles of HNO3 / 0.035 L = Concentration of HNO3

By solving for the moles of HNO3 and dividing by the volume of HNO3 in liters, you will find the concentration in molarity (M) of the HNO3 solution.

User Yunfan
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4.9k points
3 votes

Answer:

0.13M HNO3 is the concentration of the unknown

Step-by-step explanation:

Nitric acid, HNO3, reacts with NaOH as follows:

HNO3 + NaOH → H2O + NaNO3

Where 1mol HNO3 reacts with 1mol NaOH

To find the concentration of HNO3 we must find, as first, the moles NaOH added = Moles HNO3 in the solution:

30mL * (1L / 1000mL) * (0.15mol / 1L) = 0.0045 moles HNO3

In 35.0mL = 0.035L:

0.0045 moles HNO3 / 0.035L =

0.13M HNO3 is the concentration of the unknown

User Ronnie Overby
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4.7k points