रसायन विज्ञान (Chemistry) – Chemistry MCQ

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

51. The process of converting an alcohol into aldehydes or ketones using mild acidic conditions is known as:

    कOxidation खReduction गCondensation घDehydration
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    छलफल / प्रश्न उत्तरमा गल्ती छ

    पठाउनुहोस्

    टिप्पणी जाँचपछि मात्र देखिन्छ।

52. The reaction of 2 moles of potassium manganate(II) with acidified potassium dichromate solution results in a colour change from purple to green. This is because:

    कPotassium dichromate reduces MnO₄⁻ to Mn²⁺. खPotassium manganate(II) oxidizes Cr₂O₇²⁻ to Cr³⁺. गBoth potassium manganate(II) and potassium dichromate are reduced. घThe reaction forms a complex precipitate that absorbs light.
    💬 टिप्पणी / गल्ती रिपोर्ट (०)

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53. Which of the following statements regarding acids and bases is correct according to the Arrhenius definition?

    कAcids are substances that produce hydroxide ions (OH⁻) in aqueous solution. खBases are substances that produce hydrogen ions (H⁺) in aqueous solution. गAcids are substances that accept electrons, while bases donate electrons. घAcids are substances that increase the concentration of OH⁻ when dissolved in water.
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54. A solution is prepared containing 0.2 M potassium chloride (KCl) and 0.1 M sodium sulfate (Na₂SO₄) in water. What is the concentration of chloride ions (Cl⁻) in this solution?

    क0.3 M ख0.2 M ग0.1 M घ0.4 M
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55. The decomposition of lead(II) iodide (PbI₂) produces iodine (I₂) and lead (Pb). The balanced chemical equation for this reaction is: PbI₂(s) → I₂(s) + Pb(s). If 10 grams of PbI₂ decomposes, what mass of iodine will be produced?

    क2.46 g ख5.83 g ग1.23 g घ10 g
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56. Which of the following statements regarding the oxidation state of sulfur in various compounds is correct?

    कS has an oxidation state of +6 in SO₃ and +2 in H₂S खS always has an oxidation state of +4 in all its compounds गS has an oxidation state of +6 in H₂S and +2 in SO₃ घS can have different oxidation states depending on the compound
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57. The enthalpy change (ΔH) for the reaction N₂(g) + 3H₂(g) → 2NH₃(g) is -92.2 kJ/mol. What is the heat absorbed by a system when 3 moles of NH₃ are produced?

    क-92.2 kJ ख184.4 kJ ग274.6 kJ घ-274.6 kJ
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58. The process of converting an alcohol to its corresponding alkyl halide using concentrated hydrochloric acid is called:

    कReduction खOxidation गHalogenation घEsterification
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59. The reaction of ethanol with excess HI produces which major product?

    कEthane खEthyl iodide ग1-Iodoethane घEthyl alcohol
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60. The half-life of a radioactive isotope is 20 years. What fraction of the original sample will remain after 60 years?

    क1/8 ख1/4 ग1/2 घ3/4
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    टिप्पणी जाँचपछि मात्र देखिन्छ।