1. (i) Sodium (Na) is oxidised as it gains oxygen and oxygen gets reduced. (ii) Copper oxide (CuO) is reduced to copper (Cu) while hydrogen (H₂) gets oxidised to water (H₂O). For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-1/

    (i) Sodium (Na) is oxidised as it gains oxygen and oxygen gets reduced.
    (ii) Copper oxide (CuO) is reduced to copper (Cu) while hydrogen (H₂) gets oxidised to water (H₂O).

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-1/

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  2. Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride. 𝑁𝑎₂𝐶𝑂₃+𝐶𝑎𝐶𝑙₂→ 𝐶𝑎𝐶𝑂₃ +2𝑁𝑎𝐶𝑙 In this reaction, sodium carbonate and calcium chloride exchange ions to form two new compounds. Hence, it is a double displacement reaction.

    Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride.
    𝑁𝑎₂𝐶𝑂₃+𝐶𝑎𝐶𝑙₂→ 𝐶𝑎𝐶𝑂₃ +2𝑁𝑎𝐶𝑙
    In this reaction, sodium carbonate and calcium chloride exchange ions to form two new compounds. Hence, it is a double displacement reaction.

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  3. When an iron nail is dipped in a copper sulphate solution, iron (which is more reactive than copper) displaces copper from copper sulphate solution forming iron sulphate, which is green in colour. 𝐶𝑢𝑆𝑂₄+𝐹𝑒 → 𝐹𝑒𝑆𝑂₄+𝐶𝑢 Therefore, the blue colour of copper sulphate solution fades and green colour appeaRead more

    When an iron nail is dipped in a copper sulphate solution, iron (which is more reactive than copper) displaces copper from copper sulphate solution forming iron sulphate, which is green in colour.
    𝐶𝑢𝑆𝑂₄+𝐹𝑒 → 𝐹𝑒𝑆𝑂₄+𝐶𝑢
    Therefore, the blue colour of copper sulphate solution fades and green colour appears.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-1/

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  4. During the Electrolysis of water, hydrogen and oxygen is get separated by the electricity. Water (H2O) contains two parts hydrogen and one part oxygen. Since hydrogen goes to one test tube and oxygen goes to another, the amount of gas collected in one of the test tubes is double of the amount collecRead more

    During the Electrolysis of water, hydrogen and oxygen is get separated by the electricity. Water (H2O) contains two parts hydrogen and one part oxygen. Since hydrogen goes to one test tube and oxygen goes to another, the amount of gas collected in one of the test tubes is double of the amount collected in the other.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-1/

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  5. (i) The substance ‘X’ is calcium oxide. Its chemical formula is CaO. (ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime) 𝐶𝑎𝑂+𝐻₂𝑂 → 𝐶𝑎(𝑂𝐻)₂

    (i) The substance ‘X’ is calcium oxide. Its chemical formula is CaO.
    (ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime)
    𝐶𝑎𝑂+𝐻₂𝑂 → 𝐶𝑎(𝑂𝐻)₂

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