1. Copper reacts with moist carbon dioxide in air to form copper carbonate and as a result, copper vessel loses its shiny brown surface forming a green layer of copper carbonate. The citric acid present in the lemon or tamarind neutralises the basis copper carbonate and dissolves the layer. That is whyRead more

    Copper reacts with moist carbon dioxide in air to form copper carbonate and as a result, copper vessel loses its shiny brown surface forming a green layer of copper carbonate. The citric acid present in the lemon or tamarind neutralises the basis copper carbonate and dissolves the layer. That is why, tarnished copper vessels are cleaned with lemon or tamarind juice to give the surface of the copper vessel its characteristic lustre.

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  2. • Oiling, greasing, or painting: By applying oil, grease, or paint, the surface becomes water proof and the moisture and oxygen present in the air cannot come into direct contact with iron. Hence, rusting is prevented. • Galvanisation: An iron article is coated with a layer of zinc metal, which prevRead more

    • Oiling, greasing, or painting: By applying oil, grease, or paint, the surface becomes water proof and the moisture and oxygen present in the air cannot come into direct contact with iron. Hence, rusting is prevented.
    • Galvanisation: An iron article is coated with a layer of zinc metal, which prevents the iron to come in contact with oxygen and moisture. Hence, rusting is prevented.

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  3. (a) (i) There will be no action on dry litmus paper. (ii) Since the gas is sulphur dioxide (SO₂), it turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/scRead more

    (a) (i) There will be no action on dry litmus paper.
    (ii) Since the gas is sulphur dioxide (SO₂), it turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.

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  4. In the electrolytic refining of a metal M: Anode → Impure metal M Cathode → Thin strip of pure metal M Electrolyte → Solution of salt of the metal M For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-3/

    In the electrolytic refining of a metal M:
    Anode → Impure metal M
    Cathode → Thin strip of pure metal M
    Electrolyte → Solution of salt of the metal M

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  5. Metals that are more reactive than hydrogen displace it from dilute acids. For example: sodium and potassium. Metals that are less reactive than hydrogen do not displace it. For example: copper and silver. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/scieRead more

    Metals that are more reactive than hydrogen displace it from dilute acids.
    For example: sodium and potassium.
    Metals that are less reactive than hydrogen do not displace it.
    For example: copper and silver.

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    https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-3/

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