आईओई इन्जिनियरिङ प्रवेश (त्रिवि) BE / B.Arch प्रवेश परीक्षा तयारी
आईओई इन्जिनियरिङ प्रवेश (त्रिवि) – BE / B.Arch प्रवेश परीक्षा
IOE BE / B.Arch Entrance · IOE Entrance (TU)
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
BE/B.Arch 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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The monomer of polyvinyl chloride (PVC) is:
सही उत्तर: घ) CH₂=CHCl
PVC is formed by addition polymerisation of vinyl chloride (chloroethene). CF₂=CF₂ is the monomer of Teflon.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The reaction of a carboxylic acid with an alcohol in the presence of conc. H₂SO₄ to form an ester is called:
सही उत्तर: ग) Esterification
Acid-catalysed reaction of RCOOH with R'OH gives RCOOR' + H₂O (Fischer esterification). Saponification is the reverse type of reaction, alkaline hydrolysis of an ester.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Acetylene (ethyne) is prepared in the laboratory by the action of water on:
सही उत्तर: ख) Calcium carbide
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂. Aluminium carbide with water gives methane instead.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The order of stability of carbocations is:
सही उत्तर: क) 3° > 2° > 1° > CH₃⁺
Alkyl groups stabilise a carbocation by the +I effect and hyperconjugation, so tertiary is most stable and methyl least. Free radicals follow the same order.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which compound shows geometrical (cis–trans) isomerism?
सही उत्तर: घ) But-2-ene
In but-2-ene each double-bonded carbon has two different groups (H and CH₃), allowing cis and trans forms. In but-1-ene, one double-bonded carbon has two hydrogens, so no geometrical isomers exist.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following compounds is optically active?
सही उत्तर: ग) Butan-2-ol
In butan-2-ol, C-2 bears four different groups (H, OH, CH₃, C₂H₅), so it is chiral. In propan-2-ol, C-2 carries two identical CH₃ groups and is not chiral.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The general formula of a Grignard reagent is:
सही उत्तर: ख) RMgX
Grignard reagents are alkyl/aryl magnesium halides prepared from RX and Mg in dry ether. RLi is an organolithium compound, not a Grignard reagent.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Heating sodium acetate with soda lime (NaOH + CaO) gives:
सही उत्तर: क) Methane
Soda-lime decarboxylation removes CO₂ from CH₃COONa to give CH₄, an alkane with one carbon fewer. Ethane is the product of Kolbe's electrolysis.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which aldehyde undergoes the Cannizzaro reaction?
सही उत्तर: ग) Benzaldehyde
The Cannizzaro reaction needs an aldehyde with no α-hydrogen, such as benzaldehyde or formaldehyde. Acetaldehyde has α-hydrogens and undergoes aldol condensation instead.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Aniline reacts with NaNO₂ and dilute HCl at 0–5 °C to form:
सही उत्तर: ख) Benzenediazonium chloride
This is diazotisation; low temperature is needed because benzenediazonium chloride decomposes at higher temperature. On warming, it hydrolyses to phenol.
💬 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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