Concentration Terms for Competitive Exam Success

Concentration Terms

Q. If 5 moles of KCl are dissolved in 3 kg of water, what is the molality of the solution?

A. 1.67 m
B. 2.5 m
C. 1.25 m
D. 0.5 m

Solution

Molality (m) = moles of solute / kg of solvent = 5 moles / 3 kg = 1.67 m.

Correct Answer: A — 1.67 m

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Q. If 50 g of KCl is dissolved in 250 mL of solution, what is the molarity? (Molar mass of KCl = 74.5 g/mol)

A. 2.68 M
B. 1.34 M
C. 0.67 M
D. 0.25 M

Solution

Moles of KCl = 50 g / 74.5 g/mol = 0.672 moles. Molarity = 0.672 moles / 0.25 L = 2.688 M.

Correct Answer: B — 1.34 M

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Q. If 50 grams of a solute is dissolved in 200 mL of solution, what is the mass/volume percent concentration?

A. 25%
B. 20%
C. 15%
D. 10%

Solution

Mass/volume percent = (mass of solute / volume of solution) * 100 = (50 g / 200 mL) * 100 = 25%.

Correct Answer: A — 25%

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Q. If 50 grams of NaCl is dissolved in 1 liter of solution, what is the molarity? (Molar mass of NaCl = 58.5 g/mol)

A. 0.85 M
B. 1.0 M
C. 1.5 M
D. 2.0 M

Solution

Moles of NaCl = 50 g / 58.5 g/mol = 0.854 moles. Molarity = 0.854 moles / 1 L = 0.854 M.

Correct Answer: B — 1.0 M

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Q. If 50 grams of NaOH is dissolved in 1 liter of solution, what is the molarity? (Molar mass of NaOH = 40 g/mol)

A. 1.25 M
B. 2.5 M
C. 0.5 M
D. 1 M

Solution

Moles of NaOH = 50 g / 40 g/mol = 1.25 moles. Molarity = 1.25 moles / 1 L = 1.25 M.

Correct Answer: B — 2.5 M

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Q. If 50 mL of a 2 M HCl solution is diluted to 200 mL, what is the new molarity?

A. 0.25 M
B. 0.5 M
C. 1 M
D. 2 M

Solution

Using the dilution formula M1V1 = M2V2, (2 M)(50 mL) = M2(200 mL) => M2 = 0.5 M.

Correct Answer: B — 0.5 M

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Q. What is the concentration in g/L of a solution containing 0.5 moles of KCl in 1.5 L of solution? (Molar mass of KCl = 74.5 g/mol)

A. 24.83 g/L
B. 49.67 g/L
C. 37.25 g/L
D. 50 g/L

Solution

Mass of KCl = 0.5 moles × 74.5 g/mol = 37.25 g. Concentration = 37.25 g / 1.5 L = 24.83 g/L.

Correct Answer: B — 49.67 g/L

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Q. What is the concentration in molality of a solution made by dissolving 5 moles of solute in 3 kg of solvent?

A. 1.67 m
B. 2 m
C. 1.5 m
D. 2.5 m

Solution

Molality (m) = moles of solute / kg of solvent = 5 moles / 3 kg = 1.67 m.

Correct Answer: B — 2 m

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Q. What is the concentration in molarity of a solution that contains 0.5 moles of solute in 1.5 liters of solution?

A. 0.33 M
B. 0.5 M
C. 0.75 M
D. 1 M

Solution

Molarity (M) = moles of solute / liters of solution = 0.5 moles / 1.5 L = 0.33 M.

Correct Answer: C — 0.75 M

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Q. What is the concentration in ppm of a solution containing 1 gram of solute in 1 liter of solution?

A. 1000 ppm
B. 100 ppm
C. 10 ppm
D. 1 ppm

Solution

PPM = (mass of solute in grams / volume of solution in liters) * 10^6 = (1 g / 1 L) * 10^6 = 1000 ppm.

Correct Answer: A — 1000 ppm

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Q. What is the equivalent weight of H2SO4 if its molar mass is 98 g/mol?

A. 49 g
B. 98 g
C. 196 g
D. 24.5 g

Solution

Equivalent weight = molar mass / number of equivalents = 98 g/mol / 2 = 49 g.

Correct Answer: A — 49 g

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Q. What is the mass percent of a solution containing 20 g of NaCl in 180 g of water?

A. 10%
B. 20%
C. 25%
D. 15%

Solution

Mass percent = (mass of solute / total mass) x 100 = (20 g / (20 g + 180 g)) x 100 = 10%.

Correct Answer: A — 10%

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Q. What is the mass percent of a solution containing 20 g of solute in 180 g of solution?

A. 10%
B. 20%
C. 25%
D. 15%

Solution

Mass percent = (mass of solute / mass of solution) x 100 = (20 g / 200 g) x 100 = 10%.

Correct Answer: B — 20%

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Q. What is the mass percent of a solution containing 20 g of solute in 200 g of solution?

A. 10%
B. 20%
C. 5%
D. 15%

Solution

Mass percent = (mass of solute / mass of solution) × 100 = (20 g / 200 g) × 100 = 10%.

Correct Answer: B — 20%

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Q. What is the molality of a solution containing 3 moles of KCl dissolved in 1 kg of water?

A. 3 m
B. 1.5 m
C. 2 m
D. 4 m

Solution

Molality (m) = moles of solute / kg of solvent = 3 moles / 1 kg = 3 m.

Correct Answer: A — 3 m

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Q. What is the molality of a solution prepared by dissolving 3 moles of KCl in 1 kg of water?

A. 3 m
B. 1.5 m
C. 2 m
D. 4 m

Solution

Molality (m) = moles of solute / kg of solvent = 3 moles / 1 kg = 3 m.

Correct Answer: A — 3 m

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Q. What is the molarity of a solution if 10 g of glucose (C6H12O6) is dissolved in 250 mL of water? (Molar mass = 180 g/mol)

A. 0.22 M
B. 0.5 M
C. 0.75 M
D. 1 M

Solution

Moles of glucose = 10 g / 180 g/mol = 0.0556 moles. Molarity = 0.0556 moles / 0.25 L = 0.222 M.

Correct Answer: A — 0.22 M

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Q. What is the molarity of a solution if 10 grams of CaCl2 is dissolved in 250 mL of solution? (Molar mass of CaCl2 = 110 g/mol)

A. 0.25 M
B. 0.5 M
C. 1 M
D. 2 M

Solution

Moles of CaCl2 = 10 g / 110 g/mol = 0.0909 moles. Molarity = 0.0909 moles / 0.25 L = 0.3636 M.

Correct Answer: B — 0.5 M

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Q. What is the molarity of a solution prepared by dissolving 5 moles of NaCl in 2 liters of water?

A. 2.5 M
B. 5 M
C. 10 M
D. 1 M

Solution

Molarity (M) = moles of solute / liters of solution = 5 moles / 2 L = 2.5 M.

Correct Answer: A — 2.5 M

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Q. What is the mole fraction of solute in a solution containing 2 moles of solute and 8 moles of solvent?

A. 0.2
B. 0.25
C. 0.5
D. 0.1

Solution

Mole fraction of solute = moles of solute / (moles of solute + moles of solvent) = 2 / (2 + 8) = 2 / 10 = 0.2.

Correct Answer: B — 0.25

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Q. What is the normality of a solution containing 1 mole of H2SO4 in 1 liter of solution?

A. 1 N
B. 2 N
C. 0.5 N
D. 4 N

Solution

Normality (N) = equivalents of solute / liters of solution. H2SO4 provides 2 equivalents, so N = 2 moles / 1 L = 2 N.

Correct Answer: B — 2 N

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Q. What is the normality of a solution containing 2 moles of H2SO4 in 1 liter of solution?

A. 2 N
B. 4 N
C. 1 N
D. 0.5 N

Solution

Normality (N) = equivalents of solute / liters of solution. H2SO4 provides 2 equivalents, so 2 moles × 2 = 4 N.

Correct Answer: B — 4 N

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Q. What is the normality of a solution containing 3 moles of H2SO4 in 2 liters of solution? (H2SO4 is a diprotic acid)

A. 3 N
B. 6 N
C. 1.5 N
D. 1 N

Solution

Normality (N) = equivalents of solute / liters of solution. H2SO4 has 2 equivalents per mole, so 3 moles = 6 equivalents. Normality = 6 equivalents / 2 L = 3 N.

Correct Answer: B — 6 N

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Q. What is the normality of a solution containing 4 moles of H2SO4 in 2 liters of solution?

A. 4 N
B. 8 N
C. 2 N
D. 1 N

Solution

Normality (N) = equivalents of solute / liters of solution. H2SO4 has 2 equivalents, so 4 moles = 8 equivalents. N = 8 eq / 2 L = 4 N.

Correct Answer: B — 8 N

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Q. What is the normality of a solution containing 4 moles of H2SO4 in 2 liters of solution? (H2SO4 is a diprotic acid)

A. 4 N
B. 2 N
C. 8 N
D. 1 N

Solution

Normality (N) = number of equivalents / liters of solution. H2SO4 has 2 equivalents per mole, so 4 moles = 8 equivalents. Normality = 8 equivalents / 2 L = 4 N.

Correct Answer: C — 8 N

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Q. What is the normality of a solution that is 1 M in H2SO4?

A. 1 N
B. 2 N
C. 0.5 N
D. 4 N

Solution

Normality (N) = Molarity (M) x number of equivalents. H2SO4 has 2 acidic protons, so 1 M x 2 = 2 N.

Correct Answer: B — 2 N

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Q. What is the percentage by mass of a solution containing 20 grams of solute in 180 grams of solution?

A. 10%
B. 20%
C. 15%
D. 25%

Solution

Percentage by mass = (mass of solute / mass of solution) * 100 = (20 g / (20 g + 180 g)) * 100 = 20%.

Correct Answer: B — 20%

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Q. What is the percentage by mass of a solution containing 5 g of NaCl in 95 g of water?

A. 5%
B. 10%
C. 15%
D. 20%

Solution

Percentage by mass = (mass of solute / total mass) × 100 = (5 g / (5 g + 95 g)) × 100 = 5%.

Correct Answer: A — 5%

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Q. What is the volume of 1 M NaOH solution required to obtain 0.5 moles of NaOH?

A. 0.5 L
B. 1 L
C. 2 L
D. 0.25 L

Solution

Using the formula M = moles/volume, Volume = moles/M = 0.5 moles / 1 M = 0.5 L.

Correct Answer: A — 0.5 L

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Q. What is the volume of a 2 M solution that contains 4 moles of solute?

A. 2 L
B. 4 L
C. 1 L
D. 0.5 L

Solution

Volume = moles of solute / molarity = 4 moles / 2 M = 2 L.

Correct Answer: B — 4 L

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Concentration Terms MCQ & Objective Questions

Understanding concentration terms is crucial for students preparing for exams, as these concepts frequently appear in various subjects. Practicing MCQs and objective questions on concentration terms not only enhances your grasp of the topic but also boosts your confidence in tackling exam questions. Engaging with practice questions helps identify important questions and solidifies your exam preparation strategy.

What You Will Practise Here

Definitions of concentration terms such as molarity, molality, and normality.
Key formulas related to concentration calculations.
Understanding the differences between various concentration measures.
Real-life applications of concentration concepts in chemistry.
Diagrams illustrating concentration concepts for better visualization.
Sample problems and their step-by-step solutions.
Common units of concentration and their conversions.

Exam Relevance

Concentration terms are a significant part of the curriculum for CBSE, State Boards, NEET, and JEE. Students can expect questions that require them to calculate concentrations, interpret data, or apply concepts to real-world scenarios. Common question patterns include direct calculations, conceptual understanding, and application-based problems, making it essential to master this topic for success in exams.

Common Mistakes Students Make

Confusing molarity with molality and using them interchangeably.
Neglecting to account for temperature changes when calculating concentrations.
Overlooking the significance of units in concentration calculations.
Misinterpreting questions that ask for the concentration of solutions in different contexts.
Failing to practice enough problems, leading to a lack of confidence during exams.

FAQs

Question: What is the difference between molarity and molality?
Answer: Molarity is the number of moles of solute per liter of solution, while molality is the number of moles of solute per kilogram of solvent.

Question: How can I improve my understanding of concentration terms?
Answer: Regular practice of MCQs and solving objective questions will help reinforce your understanding and application of concentration terms.

Start solving practice MCQs on concentration terms today to test your understanding and enhance your exam readiness. Remember, consistent practice is key to mastering this essential topic!

Concentration Terms

Concentration Terms MCQ & Objective Questions

What You Will Practise Here

Exam Relevance

Common Mistakes Students Make

FAQs

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