रसायन विज्ञान – Chemistry MCQ
रसायन विज्ञान – कृषि/वन प्रवेश
Chemistry · Agriculture, Veterinary & Forestry Entrance · ४०९ प्रश्न
४०९ प्रश्न उपलब्ध। मोड छान्नुहोस्:
रसायन विज्ञान: 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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Which of the following is a strong oxidizing agent?
सही उत्तर: ग) Potassium permanganate (KMnO₄)
Potassium permanganate (KMnO₄) is a powerful oxidizing agent, readily accepting electrons. Sodium, magnesium, and iron are generally weak reducing agents compared to KMnO₄.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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What type of chemical bond is primarily responsible for the structure of water (H₂O)?
सही उत्तर: ख) Covalent bonds
Water molecules are held together by covalent bonds between hydrogen and oxygen atoms within each molecule. These bonds involve sharing electrons. Ionic, metallic and hydrogen bonds describe different types of interactions that exist in other compounds.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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What is the molar mass of sodium chloride (NaCl)?
सही उत्तर: क) 105.94 g/mol
Sodium chloride (NaCl) has an atomic weight of approximately 22.99 for sodium and 35.45 for chlorine. Therefore, the molar mass is 22.99 + 35.45 = 58.44 g/mol. The other options represent incorrect molar masses of different compounds.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which principle dictates that electrons within an atom will fill orbitals sequentially, maximizing the number of electrons in each orbital before any orbital receives a second electron?
सही उत्तर: ख) Hund's Rule
Hund's rule explains the filling of orbitals with parallel spins before pairing, while the Pauli exclusion principle prevents identical quantum numbers. VSEPR theory describes the shapes of molecules based on electron pair repulsion, and the octet rule is a general guideline for bonding.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following elements has the electronic configuration 2, 8, 8, 1?
सही उत्तर: ख) Potassium
The configuration 2, 8, 8, 1 corresponds to an atomic number of 19, which is potassium.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following is a nitrogenous fertiliser?
सही उत्तर: क) Calcium ammonium nitrate
CAN supplies nitrogen; rock phosphate supplies phosphorus, gypsum supplies calcium and sulphur, and KCl supplies potassium.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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How many grams of glucose (C₆H₁₂O₆, molar mass 180 g/mol) are present in 1 L of a 0.5 M glucose solution?
सही उत्तर: ख) 90 g
Mass = molarity × molar mass × volume = 0.5 × 180 × 1 = 90 g.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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When ammonium chloride is heated with slaked lime, the gas evolved is:
सही उत्तर: ख) ammonia
2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2H₂O + 2NH₃; this is the usual laboratory preparation of ammonia.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The pH of a solution whose hydrogen ion concentration is 2 × 10⁻³ M is about (log 2 = 0.30):
सही उत्तर: ग) 2.7
pH = −log(2 × 10⁻³) = 3 − log 2 = 3 − 0.30 = 2.7.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The pH of pure water at 25 °C is:
सही उत्तर: ग) 7
In pure water [H⁺] = 1 × 10⁻⁷ M, so pH = 7 (neutral).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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