(a) The bond formed between X and Y is a covalent bond, because element X (carbon) shares its valence electrons with element Y (hydrogen - like or sodium) to achieve a stable configuration. (b) Four valence electrons from X and one valence electron from Y participate in bond formation, as X needs toRead more
(a) The bond formed between X and Y is a covalent bond, because element X (carbon) shares its valence electrons with element Y (hydrogen – like or sodium) to achieve a stable configuration.
(b) Four valence electrons from X and one valence electron from Y participate in bond formation, as X needs to share electrons to complete its octet.
(c) The chemical formula of the compound is , as X forms four single bonds with four Y atoms.
(d) The compound is generally a poor conductor of electricity because covalent compounds do not have free ions or electrons to conduct current.
(e) When element Y (like Na) reacts with ethanoic acid , hydrogen gas is evolved, and the salt sodium ethanoate is formed.
Case A: Significant corrosion will be observed on the metal surface because the protective zinc coating on the metal readily react with oxygen and the moisture present in the moist air. Case B: No corrosion will be observed due to the oil layer with reacts with acts as a barrier and effectively inhiRead more
Case A: Significant corrosion will be observed on the metal surface because the protective zinc coating on the metal readily react with oxygen and the moisture present in the moist air.
Case B: No corrosion will be observed due to the oil layer with reacts with acts as a barrier and effectively inhibiting corrosion.
Case C: Minimal to no corrosion will be observed due to lack of moisture in the presence of dry air.
(a) The phenomenon is called dispersion of light. (b) White light is a mixture of seven colours. Each colour has a different wavelength and, hence, is refracted (bent) by the glass prism through different angles, resulting in a band of seven distinct colours. (c) To show recombination of spectrum ofRead more
(a) The phenomenon is called dispersion of light.
(b) White light is a mixture of seven colours. Each colour has a different wavelength and, hence, is refracted (bent) by the glass prism through different angles, resulting in a band of seven distinct colours.
(c) To show recombination of spectrum of white light, Newton used two prisms. The first prism disperses white light into seven colours. When this spectrum is passed through a second, inverted prism, it recombines the seven colours back into white light.
(a) Lime water turns milky because carbon dioxide gas reacts with calcium hydroxide solution to form calcium carbonate. Calcium carbonate is insoluble in water and appears as a white precipitate, giving the solution a milky appearance. This reaction is a common laboratory test for the presence of caRead more
(a) Lime water turns milky because carbon dioxide gas reacts with calcium hydroxide solution to form calcium carbonate. Calcium carbonate is insoluble in water and appears as a white precipitate, giving the solution a milky appearance. This reaction is a common laboratory test for the presence of carbon dioxide gas.
(b) When ethanoic acid reacts with sodium hydrogen carbonate, the products formed are sodium ethanoate (X), water, and carbon dioxide gas (Y). The reaction demonstrates the typical acid–carbonate reaction, producing effervescence due to carbon dioxide release. The sodium salt formed is soluble, while the gas evolved can turn lime water milky.
(c) Carbon dioxide released from the reaction is confirmed using lime water. It reacts with calcium hydroxide to form insoluble calcium carbonate, which makes the solution appear milky. The balanced reaction is:
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O. This simple test is widely used to detect carbon dioxide gas.
ANSWER: [A] Explanation: Correct option: (a) The near point of his eyes has receded away. The student can clearly see the blackboard but cannot read his textbook, which means he suffers from hypermetropia (farsightedness). In this defect, the near point of the eye shifts farther away than normal, maRead more
ANSWER: [A]
Explanation: Correct option: (a) The near point of his eyes has receded away. The student can clearly see the blackboard but cannot read his textbook, which means he suffers from hypermetropia (farsightedness). In this defect, the near point of the eye shifts farther away than normal, making nearby objects appear blurred.
The electronic configuration of elements X (2, 4) and Y (2, 8, 1) is given. Based on the information given above, answer the following questions: (a) Which type of bond is formed between X and Y? Explain with reason. (b) How many valence electrons take part in the bond formation between X and Y? Explain. (c) Give the chemical formula of the compound. (d) State one physical property of this compound based on the type of bonding. (e) Write the chemical equation for the reaction of Y with ethanoic acid.
(a) The bond formed between X and Y is a covalent bond, because element X (carbon) shares its valence electrons with element Y (hydrogen - like or sodium) to achieve a stable configuration. (b) Four valence electrons from X and one valence electron from Y participate in bond formation, as X needs toRead more
(a) The bond formed between X and Y is a covalent bond, because element X (carbon) shares its valence electrons with element Y (hydrogen – like or sodium) to achieve a stable configuration.
(b) Four valence electrons from X and one valence electron from Y participate in bond formation, as X needs to share electrons to complete its octet.
(c) The chemical formula of the compound is , as X forms four single bonds with four Y atoms.
(d) The compound is generally a poor conductor of electricity because covalent compounds do not have free ions or electrons to conduct current.
(e) When element Y (like Na) reacts with ethanoic acid , hydrogen gas is evolved, and the salt sodium ethanoate is formed.
CH3COOH + Na → CH3COONa + H2 ↑
See lessObserve the following diagram showing the conditions under which a metal ‘M’ corrodes. List your observations in each of the three cases A, B and C with the reason, if the metal ‘M’ is generally protected against corrosion by the method of galvanisation.
Case A: Significant corrosion will be observed on the metal surface because the protective zinc coating on the metal readily react with oxygen and the moisture present in the moist air. Case B: No corrosion will be observed due to the oil layer with reacts with acts as a barrier and effectively inhiRead more
Case A: Significant corrosion will be observed on the metal surface because the protective zinc coating on the metal readily react with oxygen and the moisture present in the moist air.
Case B: No corrosion will be observed due to the oil layer with reacts with acts as a barrier and effectively inhibiting corrosion.
Case C: Minimal to no corrosion will be observed due to lack of moisture in the presence of dry air.
See lessA person allowed a narrow beam of white light from the sun to enter a dark room through a small aperture and placed a glass prism in its path in such a manner that the beam falls on the face AB of the prism as shown in the figure. A screen S is placed on the other side of the prism, facing AC. On turning the prism slowly, a beautiful band of colours is obtained on the screen. It is the spectrum of sunlight. (a) Name the phenomenon due to which a prism splits the incident white light into a band of colours. (b) State the reason of getting a band of seven colours in the above case.
(a) The phenomenon is called dispersion of light. (b) White light is a mixture of seven colours. Each colour has a different wavelength and, hence, is refracted (bent) by the glass prism through different angles, resulting in a band of seven distinct colours. (c) To show recombination of spectrum ofRead more
(a) The phenomenon is called dispersion of light.
(b) White light is a mixture of seven colours. Each colour has a different wavelength and, hence, is refracted (bent) by the glass prism through different angles, resulting in a band of seven distinct colours.
(c) To show recombination of spectrum of white light, Newton used two prisms. The first prism disperses white light into seven colours. When this spectrum is passed through a second, inverted prism, it recombines the seven colours back into white light.
Labelled Ray Diagram:
See lessRakvi performed an activity by taking ethanoic acid and sodium hydrogen carbonate as shown in the diagram given below. The diagram shows an experimental setup where ethanol is oxidised to ethanoic acid using an oxidizing agent, producing CO2 gas sodium bicarbonate (NaHCO3) may be used to test the acidic nature of the product. Answer the following questions based on the given information: (i) What is the observable change when CO2 gas reacts with lime water in the in this experiment? (ii) Rakvi observed that a salt X is formed with the evolution of gas Y. Identify the salt X and evolved gas Y. (iii) Write the chemical equation of the reaction involved.
(a) Lime water turns milky because carbon dioxide gas reacts with calcium hydroxide solution to form calcium carbonate. Calcium carbonate is insoluble in water and appears as a white precipitate, giving the solution a milky appearance. This reaction is a common laboratory test for the presence of caRead more
(a) Lime water turns milky because carbon dioxide gas reacts with calcium hydroxide solution to form calcium carbonate. Calcium carbonate is insoluble in water and appears as a white precipitate, giving the solution a milky appearance. This reaction is a common laboratory test for the presence of carbon dioxide gas.
(b) When ethanoic acid reacts with sodium hydrogen carbonate, the products formed are sodium ethanoate (X), water, and carbon dioxide gas (Y). The reaction demonstrates the typical acid–carbonate reaction, producing effervescence due to carbon dioxide release. The sodium salt formed is soluble, while the gas evolved can turn lime water milky.
(c) Carbon dioxide released from the reaction is confirmed using lime water. It reacts with calcium hydroxide to form insoluble calcium carbonate, which makes the solution appear milky. The balanced reaction is:
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O. This simple test is widely used to detect carbon dioxide gas.
See lessA student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his text book. Which of the following statements is correct?
ANSWER: [A] Explanation: Correct option: (a) The near point of his eyes has receded away. The student can clearly see the blackboard but cannot read his textbook, which means he suffers from hypermetropia (farsightedness). In this defect, the near point of the eye shifts farther away than normal, maRead more
ANSWER: [A]
Explanation: Correct option: (a) The near point of his eyes has receded away. The student can clearly see the blackboard but cannot read his textbook, which means he suffers from hypermetropia (farsightedness). In this defect, the near point of the eye shifts farther away than normal, making nearby objects appear blurred.
See less