What is the molar concentration of Dinitrophenol (DNP) in a solution made by dissolving 184.107
mg DNP in one liter of water? [Molar mass: 184.107 g/mole]
1. 1000 µ𝑀
2. 1000 𝑚𝑀
3. 1000 𝑛𝑀
4. 1000 𝑝𝑀

Introduction to Molar Concentration and Dinitrophenol (DNP)

Molar concentration, also known as molarity (M), refers to the number of moles of a solute dissolved in one liter of solution. Dinitrophenol (DNP) is a chemical compound commonly used in biochemical research and metabolic studies. Understanding how to calculate the molar concentration of DNP is essential for accurate lab work and biochemical analysis. In this article, we will calculate the molar concentration of DNP when 184.107 mg of DNP is dissolved in one liter of water, step-by-step.

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Key Phrase: Molar Concentration of Dinitrophenol (DNP)

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✅ Question and Answer

Question:
What is the molar concentration of Dinitrophenol (DNP) in a solution made by dissolving 184.107 mg of DNP in one liter of water?

Options:

1. 1000 µM
2. 1000 mM
3. 1000 nM
4. 1000 pM

Correct Answer:
✔️ Option 1: 1000 µM

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Understanding Molar Concentration

Molar concentration (M) is calculated using the formula:

M=Mass of solute(g)/  Molar mass (g/mol)×Volume of solution (L)

Where:

• M = Molar concentration (in moles/liter)
• Mass of solute = Amount of solute dissolved (in grams)
• Molar mass = Molecular weight of the compound (in g/mol)
• Volume of solution = Volume of the solution (in liters)

Step-by-Step Calculation

1. Given Data:

• Mass of DNP = 184.107 mg
• Molar mass of DNP = 184.107 g/mol
• Volume of solution = 1 liter

2. Convert mg to g:

184.107mg

=184.107g/ 1000

=0.184107g

Use the Formula:

M=0.184107 g  / 184.107 g/mol×1 LM 

M=0.001M

M=1000μM

 

Correct Answer:

The molar concentration of DNP is 1000 µM. Therefore, the correct answer is Option 1.

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Why Option 1 is Correct

• The mass of DNP was accurately converted to grams.
• The molar mass and volume were correctly applied in the equation.
• The calculated molarity matches the value for 1000 µM.

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Why Other Options Are Incorrect

1000 mM – This value is too high for the given mass and molar mass.
1000 nM – This value is too low for the calculated molarity.
1000 pM – This value is extremely low and inconsistent with the given data.

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Importance of Molar Concentration in Biochemical Research

Molar concentration is a fundamental concept in biochemistry and molecular biology. It is crucial for:
 Preparing buffer solutions and reagents.
Designing enzyme kinetics experiments.
 Ensuring accurate concentrations in drug discovery and metabolic studies.
 Analyzing ligand-receptor binding affinities.

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Biological Significance of Dinitrophenol (DNP)

Dinitrophenol (DNP) is a well-known uncoupler of oxidative phosphorylation in mitochondria. It functions by:

• Disrupting the proton gradient across the inner mitochondrial membrane.
• Inhibiting ATP synthesis by allowing protons to leak back into the matrix.
• Increasing metabolic rate and heat production.

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Applications of Dinitrophenol in Research

1. Metabolic Studies: DNP is used to study mitochondrial function and metabolic disorders.
2. Weight Loss Research: DNP has been historically used (illegally) for weight loss due to its metabolic effects.
3. Cellular Respiration Studies: It helps in understanding the electron transport chain and ATP synthesis.

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How to Avoid Mistakes in Molarity Calculations

Always convert mass to grams before applying the formula.
 Ensure that the molar mass is correctly determined.
 Double-check the volume in liters, not milliliters.
Express the final concentration in appropriate units (M, mM, µM).

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Frequently Asked Questions (FAQs)

1. Why is DNP toxic to humans?

DNP disrupts ATP synthesis by uncoupling oxidative phosphorylation, leading to excessive heat production and metabolic imbalance, which can be fatal.

2. How is molarity different from molality?

• Molarity = Moles of solute per liter of solution.
• Molality = Moles of solute per kilogram of solvent.

3. What are the effects of DNP on mitochondria?

DNP increases oxygen consumption but reduces ATP production by allowing protons to bypass ATP synthase.

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Importance for Competitive Exams

Understanding molarity and DNP function is critical for success in:
CSIR NET Life Science
DBT BET JRF
IIT JAM
GATE Biotechnology

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Conclusion

The molar concentration of DNP in the given solution is 1000 µM. Molarity calculations are essential for accurate lab work and biochemical experiments. Mastering this concept will give you a competitive edge in exams like CSIR NET Life Science, DBT BET JRF, IIT JAM, and GATE Biotechnology.