1. Doctors recommend consuming iodised salt because iodine is a vital micronutrient required for the synthesis of thyroid hormones—thyroxine and triiodothyronine. These hormones control metabolism, body temperature, and overall growth. Iodine also supports brain development and nervous system functionsRead more

    Doctors recommend consuming iodised salt because iodine is a vital micronutrient required for the synthesis of thyroid hormones—thyroxine and triiodothyronine. These hormones control metabolism, body temperature, and overall growth. Iodine also supports brain development and nervous system functions. A deficiency of iodine leads to goitre, fatigue, and mental dullness. Regular intake of iodised salt prevents such disorders and helps maintain a healthy thyroid gland, ensuring the body’s proper growth, development, and energy balance.

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  2. The reddish-brown metal “X” is copper (Cu). When copper is heated in air, it reacts with oxygen to form a black compound “Y”, which is copper(II) oxide (CuO). When CuO is heated in the presence of hydrogen gas (H₂), it gets reduced back to copper metal (Cu) and water is formed. CuO + H₂ → Cu + H₂O CRead more

    The reddish-brown metal “X” is copper (Cu). When copper is heated in air, it reacts with oxygen to form a black compound “Y”, which is copper(II) oxide (CuO).
    When CuO is heated in the presence of hydrogen gas (H₂), it gets reduced back to copper metal (Cu) and water is formed.

    CuO + H₂ → Cu + H₂O

    Copper is refined by electrolysis, and its pure form is widely used in electrical wiring due to its high electrical conductivity.

    (b) Diagram to represent the process of refining of ‘X

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  3. The element M has the electronic configuration 2, 8, 3, indicating it is a metal with valency 3 (similar to aluminium). It combines with Cl⁻ to form MCl₃ and with SO₄²⁻ to form M₂(SO₄)₃. Since M loses electrons to nonmetals, the bond formed is ionic in nature. Ionic compounds consist of positive andRead more

    The element M has the electronic configuration 2, 8, 3, indicating it is a metal with valency 3 (similar to aluminium). It combines with Cl⁻ to form MCl₃ and with SO₄²⁻ to form M₂(SO₄)₃. Since M loses electrons to nonmetals, the bond formed is ionic in nature. Ionic compounds consist of positive and negative ions held by strong electrostatic forces. These compounds conduct electricity only in molten or aqueous states, as free ions are available to carry electric current in those conditions.

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  4. (a) The above reaction is known as a thermite reaction as the reaction is highly exothermic reaction. The metal (Mn/Fe) obtained will be in molten/ liquid state. (b) Substance oxidised - Al(s), Substance reduced – MnO2 (s) (c) Aluminium is preferably used in thermite reactions as it is placed aboveRead more

    (a) The above reaction is known as a thermite reaction as the reaction is highly exothermic reaction. The metal (Mn/Fe) obtained will be in molten/ liquid state.

    (b) Substance oxidised – Al(s), Substance reduced – MnO2 (s)

    (c) Aluminium is preferably used in thermite reactions as it is placed above Fe and Mn in reactivity series of metals. Al is more reactive than Fe/ Mn.

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  5. a) If 100 joules of energy are available at the third trophic level, then the producer level must have 10,000 joules of energy, as only 10% of energy is transferred at each step. Energy decreases through trophic levels due to losses in metabolic activities like respiration, movement, and heat. b) NoRead more

    a) If 100 joules of energy are available at the third trophic level, then the producer level must have 10,000 joules of energy, as only 10% of energy is transferred at each step. Energy decreases through trophic levels due to losses in metabolic activities like respiration, movement, and heat.

    b) No, it is not possible to add two more trophic levels before the fourth level, because the energy available would become too small to sustain additional organisms efficiently in the food chain.

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