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
-
Alum (Potassium Aluminum Sulfate) is added to muddy water primarily due to its ability to form insoluble precipitates. Which of the following statements accurately describes this process?
सही उत्तर: घ) It coagulates colloidal particles by neutralizing surface charges.
Alum acts as a flocculant. It neutralizes the negative charge of colloidal particles, allowing them to aggregate and form larger clumps (floc) that settle out of the water due to gravity. The other options describe different mechanisms for clarifying water but are not the primary action of alum.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
What does the term 'equivalence point' in a titration signify?
सही उत्तर: ख) The point at which one reactant has been completely neutralized
The correct answer is 'The point at which one reactant has been completely neutralized' (option 2). At the equivalence point, the moles of acid and base are equal, representing complete neutralization. The other options relate to inaccurate definitions or observation of the titration.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following acids has the highest acidity?
सही उत्तर: ख) Formic acid (HCOOH)
The correct answer is ‘Formic acid’ (option 2). Acidity of carboxylic acids increases as the number of carbon atoms increase, leading to a stronger H-bond formation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
What is the primary reason for using dilute sulfuric acid (H₂SO₄) as a catalyst in the esterification reaction between acetic acid and ethanol?
सही उत्तर: ग) It protonates the carbonyl group, making it more reactive
The correct answer is 'It protonates the carbonyl group, making it more reactive' (option 3). Sulfuric acid acts as a catalyst by protonating the carbonyl group of acetic acid, increasing its electrophilicity and facilitating the reaction. The other options are incorrect explanations for the role of sulfuric acid.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The reaction between calcium carbide and water produces acetylene gas. What is the main product formed during this reaction, besides acetylene?
सही उत्तर: क) Calcium carbonate
The correct answer is ‘Hydrogen’ (option 2). Calcium carbide (CaC₂) reacts with water to produce calcium hydroxide (Ca(OH)₂), and acetylene (C₂H₂). The other options are either byproducts or completely unrelated to the reaction.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
A solution contains 0.1 moles of a substance dissolved in water. If the volume of the solution is 2 liters, what is the molar concentration (in mol/L) of the substance?
सही उत्तर: क) 0.05 M
The molar concentration is calculated by dividing the number of moles by the volume in liters. 0.1 moles / 2 L = 0.05 M. The other options are incorrect because they do not accurately represent this calculation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The molar mass of calcium carbonate (CaCO₃) is approximately 100 g/mol. If 50g of CaCO₃ is dissolved in water, what will be the concentration of Ca²⁺ ions in the solution, assuming complete dissolution? (Ca = 40, O = 16, C = 12)
सही उत्तर: क) 0.1 M
The correct answer is 0.2 M. The balanced equation for the dissolution is CaCO₃ → Ca²⁺ + CO₃²⁻. Each mole of CaCO₃ produces one mole of Ca²⁺ ions. Since the molar mass of CaCO₃ is 100g/mol, 50g represents 0.5 moles. Therefore, the concentration of Ca²⁺ is 0.5 M. The other options are incorrect as they do not accurately reflect the stoichiometry of the reaction.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Milk of magnesia, used as an antacid, is a suspension of: (a) A covalent compound (b) An ionic compound (c) A heterogeneous mixture (d) A solution
सही उत्तर: ग) A heterogeneous mixture
Milk of magnesia (magnesium hydroxide suspension) is a heterogeneous mixture because its components (magnesium hydroxide and water) are not uniformly distributed. Options (a), (b), and (d) describe different types of chemical combinations; option (c) correctly identifies it as a heterogeneous mixture.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following compounds would exhibit the highest boiling point?
सही उत्तर: ग) Propane (C₃H₈)
Higher molecular weight hydrocarbons have higher intermolecular forces (Van der Waals forces), leading to a higher boiling point. Ethane has the highest molecular weight of the options listed.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
What does the term ‘oxidation’ refer to in chemistry?
सही उत्तर: ख) B. The removal of electrons from a substance.
Oxidation is defined as the loss of electrons by a chemical element or compound, often accompanied by an increase in oxidation state. Option A is correct; B describes reduction; C relates to carbonation and D involves acid-base neutralization.
💬 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।
नमस्ते! पाठ्यक्रम, सामान्य ज्ञान, भाषा परीक्षा वा कुनै प्रश्नको उत्तर बुझ्न सोध्नुहोस्।
AI ले गल्ती गर्न सक्छ। महत्वपूर्ण कुरा आधिकारिक स्रोतमा जाँच्नुहोस्।