इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
Engineering Entrance – Mathematics, Physics, Chemistry & English · ३,८४१ प्रश्न
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
इन्जिनियरिङ प्रवेश: 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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In Lassaigne's test, the presence of nitrogen in an organic compound is shown by the formation of a:
सही उत्तर: ख) Prussian blue colour
NaCN from fusion forms sodium ferrocyanide, which with Fe³⁺ gives Prussian blue, Fe₄[Fe(CN)₆]₃.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Liquids that decompose at or below their normal boiling points are purified by:
सही उत्तर: ग) distillation under reduced pressure
Lowering the pressure lowers the boiling point, so the liquid distils below its decomposition temperature.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The strongest base in aqueous solution among the following is:
सही उत्तर: ग) (CH₃)₂NH
In water the combined inductive and solvation effects make dimethylamine the strongest; aniline is weakest due to resonance.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The IUPAC name of CH₂=CH–CHO is:
सही उत्तर: ख) prop-2-enal
The CHO carbon is C1 and the double bond is between C2 and C3, so the name is prop-2-enal (acrolein).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Zone refining is used to obtain very pure:
सही उत्तर: क) silicon and germanium
Zone refining is based on impurities being more soluble in the melt; it gives the ultra-pure Si and Ge needed for semiconductors.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In the electrolytic extraction of aluminium from alumina, cryolite is added mainly to:
सही उत्तर: ख) lower the melting point and increase the conductivity
Cryolite (Na₃AlF₆) dissolves alumina, lowering the melting temperature of the electrolyte and improving its conductivity.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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EDTA, used in complexometric titrations, is a:
सही उत्तर: ख) hexadentate ligand
EDTA⁴⁻ binds through two nitrogen and four carboxylate oxygen atoms, so it is hexadentate.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The coordination number of iron in [Fe(C₂O₄)₃]³⁻ is:
सही उत्तर: क) 6
Oxalate is bidentate; three oxalate ligands form 3 × 2 = 6 coordinate bonds.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The metal used as a catalyst in the hydrogenation of vegetable oils to make vanaspati ghee is:
सही उत्तर: ग) nickel
Finely divided nickel catalyses the addition of hydrogen to the C=C bonds of oils.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following ions is colourless in aqueous solution?
सही उत्तर: घ) Zn²⁺
Zn²⁺ has a completely filled 3d¹⁰ configuration, so no d–d transition is possible.
💬 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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