Mole Concept — Set 2
Chemistry · मोल संकल्पना · Questions 11–20 of 40
How many moles of solute are present in 250 mL of a 2.0 M solution?
Correct Answer: C. 0.50 mol
• **0.50 mol** = Option C is correct because moles = M × V(L) = 2. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: 2.00 mol; B: 0.25 mol; D: 5.00 mol
The dilution equation for solutions is?
Correct Answer: B. M1V1 = M2V2
• **M1V1 = M2V2** = Option B is correct because during dilution, moles of solute remain constant so M1V1 = M2V2. • **1** — Option B is correct because during dilution, moles of solute remain constant ... • 💡 Wrong-option analysis: A: M1V2 = M2V1; C: M1 + V1 = M2 + V2; D: M1/M2 = V1/V2
Mass percent (% by mass) of a solute in a solution is?
Correct Answer: C. (mass of solute/mass of solution) × 100
• **(mass of solute/mass of solution) × 100** = Option C is correct because mass percent equals mass of solute divided by mass of solution times 100. • **mass** — Option C is correct because mass percent equals mass of solute divided by mas... • 💡 Wrong-option analysis: A: (moles of solute/volume of solution) × 100; B: (mass of solution/mass of solute) × 100; D: (mass of solvent/mass of solution) × 100
Molality (m) of a solution is defined as?
Correct Answer: C. Moles of solute per kilogram of solvent
• **Moles of solute per kilogram of solvent** = Option C is correct because molality is moles of solute per kg of solvent. • **mass** — It depends on mass, not volume • 💡 Wrong-option analysis: A: Moles of solvent per kilogram of solute; B: Grams of solute per liter of solution; D: Moles of solute per liter of solution
Mole fraction of a component in a mixture is?
Correct Answer: A. Moles of component/total moles of all components
• **Moles of component/total moles of all components** = Option A is correct because mole fraction is moles of a component divided by total moles. • (Contextual detail from explanation) • 💡 Wrong-option analysis: B: Volume of component/total volume; C: Mass of component/total mass; D: Moles of component/volume of solution
In a chemical reaction, the limiting reagent is the reactant that?
Correct Answer: C. Gets completely consumed first and limits product formation
• **Gets completely consumed first and limits product formation** = Option C is correct because the limiting reagent is used up first and controls the maximum product. • **first** — Option C is correct because the limiting reagent is used up first and control... • 💡 Wrong-option analysis: A: Is always present in excess; B: Has the lowest density; D: Has the highest molar mass
For the reaction 2H2 + O2 → 2H2O, if 5 mol H2 reacts with 2 mol O2, which statement is correct?
Correct Answer: D. O2 is limiting and 4 mol H2O can form
• **O2 is limiting and 4 mol H2O can form** = Option D is correct because 5 mol H2 would need 2. • **2** — Option D is correct because 5 mol H2 would need 2 • 💡 Wrong-option analysis: A: Both are limiting and 2 mol H2O can form; B: O2 is excess and 2 mol H2O can form; C: H2 is limiting and 2 mol H2O can form
What is the mass of 0.20 mol of NaCl? (Na=23, Cl=35.5)?
Correct Answer: D. 11.7 g
• **11.7 g** = Option D is correct because molar mass of NaCl = 23 + 35. • **mass** — Option D is correct because molar mass of NaCl = 23 + 35 • 💡 Wrong-option analysis: A: 5.85 g; B: 9.75 g; C: 23.0 g
In dilute aqueous solutions, 5 ppm of a solute is approximately equal to?
Correct Answer: B. 5 mg/L
• **5 mg/L** = Option B is correct because in water, 1 ppm is roughly 1 mg/L for very dilute solutions. • **1** — Option B is correct because in water, 1 ppm is roughly 1 mg/L for very dilute... • 💡 Wrong-option analysis: A: 5 g/mL; C: 5 mol/L; D: 5 g/L
How many atoms are present in 0.10 mol of sodium (Na)?
Correct Answer: A. 6.022 × 10^22 atoms
• **6.022 × 10^22 atoms** = Option A is correct because atoms = moles × NA = 0. • **22** — 022 × 10^23 • 💡 Wrong-option analysis: B: 3.011 × 10^23 atoms; C: 6.022 × 10^23 atoms; D: 3.011 × 10^22 atoms