रसायन विज्ञान (Chemistry) – Chemistry MCQ
रसायन विज्ञान (Chemistry) – CEE प्रवेश
Chemistry · Medical Entrance (CEE) – Physics, Chemistry, Biology & MAT · ४१० प्रश्न
४१० प्रश्न उपलब्ध। मोड छान्नुहोस्:
रसायन विज्ञान (Chemistry): प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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The density of solid carbon is 3.5 g/cm³. The mass of a piece of carbon that occupies a volume of 10 cm³ would be:
सही उत्तर: ग) 10 g
Density = Mass / Volume. Mass = Density × Volume. Therefore, the mass is 3.5 g/cm³ × 10 cm³ = 35 g. Options ‘3.5 g’, ‘7.0 g’ and ‘10g’ are incorrect, as they either use the volume or density value inaccurately.”}]}”,
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The titration of a monoprotic acid (HA) with a strong base (NaOH) will proceed fastest when the concentration of both solutions is:
सही उत्तर: ग) Equal
Titration rates are maximized at equal concentrations of the titrant and analyte. This ensures a constant rate of reaction until all of one reactant is consumed. Higher or lower concentrations will result in slower, less consistent reaction rates.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following oxides of nitrogen primarily contributes to the formation of smog in urban areas?
सही उत्तर: घ) NO₂
Nitrogen dioxide (NO₂) is a key component of photochemical smog. It's formed from reactions between NO and O₃ under sunlight. N₂O, N₂O₄ and NO are all associated with different stages of smog formation but NO₂ is the most directly responsible for its characteristic color and harmful effects. The other choices are often precursors to smog but aren’t primary contributors.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The reaction between hydrochloric acid (HCl) and sodium carbonate (Na₂CO₃) produces carbon dioxide gas. Which of the following observations would BEST confirm this production?
सही उत्तर: ग) Evolution of bubbles of gas.
The reaction between HCl and Na₂CO₃ is an acid-base neutralization that produces carbon dioxide gas, which escapes as bubbles. Option 2 correctly identifies this observation. The other options represent different chemical reactions or physical changes that would not confirm the production of CO₂.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The standard enthalpy of formation of H₂O(l) at 298 K is 0 kJ/mol. Which of the following reactions has the largest positive change in enthalpy?
सही उत्तर: ख) 2H₂(g) + O₂(g) → 2H₂O(l)
The reaction 2H₂(g) + O₂(g) → 2H₂O(l) is the only one that forms two moles of water from its elements, thus releasing the most energy (largest positive enthalpy change). The other options either consume water or produce steam, resulting in different enthalpy changes.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The percentage dissociation of a weak acid HA in water is 10%. If the initial concentration of HA is 0.1 M, what will be the equilibrium concentration of HA?
सही उत्तर: घ) 0.11 M
The percentage dissociation represents the fraction of the acid that dissociates (dissociated = dissociated). So 10% of 0.1M is 0.01M. The equilibrium concentration will be the initial concentration minus the amount that has dissociated, which equals 0.09M.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The solubility product constant, Ksp, for AgCl(s) is 1.8 × 10⁻¹⁰. If the concentration of Ag⁺ ions in a saturated solution is 2.4 × 10⁻⁸ M, what is the concentration of Cl⁻ ions in this saturated solution?
सही उत्तर: ख) 3.2 × 10⁻⁹ M
Ksp = [Ag⁺][Cl⁻]². Solving for [Cl⁻], we get [Cl⁻] = √(Ksp / [Ag⁺]²) = √((1.8 × 10⁻¹⁰) / (2.4 × 10⁻⁸)) ≈ 9.6 × 10⁻⁹ M. The other options do not correctly apply the Ksp equation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The approximate molarity of a solution prepared by dissolving 4 g of sodium chloride (NaCl) in 500 mL of water is (Molar mass of NaCl = 102 g/mol).
सही उत्तर: ख) 2.0 M
The molarity calculation involves converting grams of solute to moles and then dividing by the volume in liters. NaClO's molar mass is 58.44 g/mol, not 102g/mol. 4g / 58.44 g/mol = 0.069 mol. Diluting this into 500 mL (0.5 L) gives 0.069 mol / 0.5 L = 0.138 M. Therefore, the correct answer is 2.0 M.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The molar mass of ammonia (NH₃) is approximately:
सही उत्तर: ग) 31 g/mol
Molar mass of NH₃ = (14 + 3 * 1) g/mol = 17 g/mol. However, 28 g/mol is the correct molar mass for ammonia.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following is a reducing agent in the reaction: Zn + CuSO₄ → ZnSO₄ + Cu?
सही उत्तर: ख) Zn
In this reaction, Zinc (Zn) loses electrons and gets oxidized, hence acts as a reducing agent. Copper(II) sulfate (CuSO₄) is oxidized and therefore the reducing agent.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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