Introduction to the Topic

As candidates prepare for the 71st BPSC Prelims, a strong grasp of Chemistry within the General Science syllabus is essential, as illustrated by this question from the 69th BPSC Prelims (2023) on the concept of solute concentration. This topic focuses on fundamental principles of solution chemistry, crucial for understanding chemical processes in industries, environmental science, and healthcare. Such questions reflect BPSC’s emphasis on conceptual clarity and practical applications, particularly relevant to Bihar’s educational initiatives in science and technology. The question tests candidates’ ability to identify the correct term for a specific chemical property, navigating distractors to ensure precision.

Question and Options

Question: The amount of solute present per unit volume or per unit mass of the solution/solvent is known as _____ in Chemistry.
(A) Composition of solute
(B) Concentration of solvent
(C) Concentration of solute
(D) Concentration of solution

Analysis and Explanation

This question evaluates candidates’ understanding of concentration in the context of solutions, a core concept in chemistry. A solution consists of a solute (the substance dissolved) and a solvent (the medium in which the solute dissolves). The term sought describes the amount of solute relative to the solution or solvent, expressed per unit volume or mass. Let’s analyze each option systematically to identify the correct term.

• Composition of solute (A):
  The term “composition” generally refers to the makeup or proportion of components in a mixture, such as the chemical formula of a solute (e.g., NaCl for salt). However, it does not specifically denote the amount of solute per unit volume or mass of the solution or solvent. In chemistry, composition is a broader term and not used to quantify concentration in this context.
  Evaluation: Incorrect, as “composition” does not describe the quantitative measure of solute concentration.
• Concentration of solvent (B):
  Concentration typically refers to the amount of a substance (usually the solute) per unit of the solution or solvent. The “concentration of solvent” would imply measuring the solvent’s quantity relative to the solution, which is not the focus here. In most solutions (e.g., aqueous solutions), the solvent is the major component, and its concentration is less commonly quantified in this manner. The question explicitly asks about the solute, not the solvent.
  Evaluation: Incorrect, as the question pertains to the solute’s quantity, not the solvent’s.
• Concentration of solute (C):
  The concentration of solute is defined as the amount of solute present per unit volume or per unit mass of the solution or solvent. This is a standard term in chemistry, expressed in units like:
  • Molarity (moles of solute per liter of solution, mol/L).
  • Molality (moles of solute per kilogram of solvent, mol/kg).
  • Mass percentage (mass of solute per mass of solution).
  • Volume percentage (volume of solute per volume of solution).
    These measures align with the question’s description of solute amount per unit volume (e.g., molarity) or per unit mass (e.g., molality) of the solution or solvent. For example, in a saltwater solution, the concentration of salt (solute) might be 0.1 mol/L or 5 g/L of the solution.
    Evaluation: Correct, as “concentration of solute” precisely describes the amount of solute per unit volume or mass of the solution or solvent.
• Concentration of solution (D):
  The term “concentration of solution” is less specific and not a standard phrase in chemistry. Concentration typically refers to the solute’s quantity within the solution, not the solution as a whole. While the solution’s overall concentration might imply the solute’s contribution, the question focuses on the solute specifically. This option is vague and could mislead candidates into thinking it encompasses the entire solution rather than the solute’s proportion.
  Evaluation: Incorrect, as the term is imprecise and does not directly address the solute’s concentration.

Key Insights:

• Concentration is a quantitative measure, critical in applications like chemical manufacturing, pharmaceuticals, and environmental monitoring.
• The question emphasizes the solute, distinguishing it from the solvent or the solution as a whole.
• Distractors test candidates’ ability to avoid vague or incorrect terms (e.g., “composition” or “solution concentration”) and focus on precise chemical terminology.
• The question’s moderate difficulty lies in requiring a clear understanding of solution chemistry terminology amidst closely related options.

Correct Answer

Correct Answer: (C) Concentration of solute
Reason: The concentration of solute refers to the amount of solute present per unit volume or per unit mass of the solution or solvent, as described in the question. This is a standard term in chemistry, expressed through measures like molarity or molality. Options A, B, and D are incorrect, as they either use imprecise terms (composition, solution concentration) or refer to the wrong component (solvent).

Five Probable Questions of Similar Difficulty

To enhance preparation for the 71st BPSC Prelims, here are five chemistry-related questions of comparable difficulty, focusing on solutions and concentration, with brief explanations:

1. Question: Which unit expresses the concentration of a solute in moles per liter of solution?
   • (A) Molality
   • (B) Molarity
   • (C) Mass percentage
   • (D) Volume percentage
     Answer: (B) Molarity
     Explanation: Molarity (mol/L) measures solute moles per liter of solution, unlike molality (per kg of solvent) or percentages.
2. Question: In a solution, the substance that dissolves the solute is called:
   • (A) Solvent
   • (B) Solute
   • (C) Solution
   • (D) Mixture
     Answer: (A) Solvent
     Explanation: The solvent is the medium (e.g., water) that dissolves the solute to form a solution.
3. Question: What term describes the concentration of a solute in moles per kilogram of solvent?
   • (A) Molarity
   • (B) Molality
   • (C) Normality
   • (D) Mole fraction
     Answer: (B) Molality
     Explanation: Molality measures solute moles per kg of solvent, useful in temperature-dependent calculations.
4. Question: A solution with a high concentration of solute is described as:
   • (A) Dilute
   • (B) Saturated
   • (C) Concentrated
   • (D) Supersaturated
     Answer: (C) Concentrated
     Explanation: A concentrated solution has a high solute amount relative to the solvent, unlike dilute or saturated solutions.
5. Question: Which measure of concentration is expressed as the mass of solute per 100 g of solution?
   • (A) Molarity
   • (B) Molality
   • (C) Mass percentage
   • (D) Volume percentage
     Answer: (C) Mass percentage
     Explanation: Mass percentage is the mass of solute per 100 g of solution, a common concentration unit.

Key Terms Explained

• Concentration of Solute: Amount of solute per unit volume (e.g., mol/L) or mass (e.g., mol/kg) of solution or solvent.
• Solute: Substance dissolved in a solution (e.g., salt in saltwater).
• Solvent: Medium that dissolves the solute (e.g., water in saltwater).
• Solution: Homogeneous mixture of solute and solvent.
• Molarity: Concentration unit as moles of solute per liter of solution (mol/L).
• Molality: Concentration unit as moles of solute per kilogram of solvent (mol/kg).
• Mass Percentage: Concentration as mass of solute per 100 g of solution.
• Photoelectric Effect: Conversion of light energy to electrical energy, relevant to energy-related chemistry applications.

Preparation Strategies for 71st BPSC Prelims

To excel in chemistry questions like this for the 71st BPSC Prelims, adopt these targeted strategies:

• Understand Solution Chemistry: Study key terms like solute, solvent, and concentration, focusing on units like molarity and molality.
• Memorize Definitions: Retain precise definitions of chemical terms to distinguish between similar options (e.g., solute vs. solution concentration).
• Practice Application-Based Questions: Solve problems involving concentration calculations to reinforce conceptual understanding.
• Link to Real-World Uses: Relate solution chemistry to applications in pharmaceuticals, agriculture, or environmental science, relevant to Bihar’s context.
• Tackle Mock Tests: Practice objective questions under timed conditions to enhance accuracy and manage negative marking (1/3rd per wrong answer).

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• Website: Download mock tests, previous year papers (e.g., 69th BPSC Prelims), and structured study materials.

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Enhance your preparation with Crack Target’s tailored offerings:

• Comprehensive Notes: Study detailed materials on General Science, including solution chemistry and its practical applications.
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• Current Affairs Integration: Stay updated on chemical advancements and their societal impact, critical for Prelims and Mains.
• Expert Support: Attend doubt-clearing sessions to clarify concepts like concentration and solution terminology.

By leveraging Crack Target’s resources, aspirants can confidently tackle chemistry-related questions, securing a competitive edge in the 71st BPSC Prelims. For additional 69th BPSC questions or specific topics, please share, and I’ll provide a professional response with a distinct, engaging style, maintaining professional language as requested.