रसायन विज्ञान (Chemistry) – Chemistry MCQ
रसायन विज्ञान (Chemistry) – इन्जिनियरिङ प्रवेश
Chemistry · Engineering Entrance – Mathematics, Physics, Chemistry & English · ७२८ प्रश्न
७२८ 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 structure of hydrogen peroxide (H₂O₂) is:
सही उत्तर: ग) non-planar (open-book)
The two O–H bonds lie in different planes (dihedral angle about 111° in the gas phase), giving an open-book, non-planar structure.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Dilute solutions of alkali metals in liquid ammonia are blue because of:
सही उत्तर: ख) ammoniated (solvated) electrons
The metal ionises to give ammoniated cations and ammoniated electrons, and the solvated electrons absorb in the visible region, giving the blue colour.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Physical adsorption (physisorption) of a gas on a solid generally:
सही उत्तर: क) decreases with increase in temperature
Physisorption is exothermic with weak van der Waals forces, so by Le Chatelier's principle it decreases as temperature rises.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The scattering of a beam of light by colloidal particles, making its path visible, is called the:
सही उत्तर: घ) Tyndall effect
Colloidal particles are large enough to scatter light, so the beam becomes visible; true solutions do not show the Tyndall effect.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The half-life of a first-order reaction:
सही उत्तर: ग) is independent of the initial concentration
For first order, t½ = 0.693/k, which contains no concentration term.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The Arrhenius equation relating the rate constant k to temperature T is:
सही उत्तर: ख) k = A e^(−Ea/RT)
k = A e^(−Ea/RT), where A is the frequency factor and Ea the activation energy.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which statement about the molecularity of an elementary reaction is correct?
सही उत्तर: क) It can never be zero or fractional
Molecularity is the number of species colliding in an elementary step, so it is a whole number (1, 2 or rarely 3); order can be zero or fractional.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The chemical composition of rust is:
सही उत्तर: घ) Fe₂O₃·xH₂O
Rust is hydrated iron(III) oxide, Fe₂O₃·xH₂O, formed by electrochemical corrosion of iron in moist air.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A common unit of molar conductivity is:
सही उत्तर: ग) S cm² mol⁻¹
Λm = κ/C; with κ in S cm⁻¹ and C in mol cm⁻³, Λm is in S cm² mol⁻¹.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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According to Faraday's second law of electrolysis, when the same quantity of electricity is passed through different electrolytes, the masses of substances liberated are proportional to their:
सही उत्तर: ख) equivalent weights
Equal charge liberates equal numbers of equivalents, so the masses deposited are in the ratio of the equivalent weights.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
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