1. Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate. Na2SO4(aq)+BaCl2(aq)→BaSO4s+2NaCl(aq) In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate ofRead more

    Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate.
    Na2SO4(aq)+BaCl2(aq)BaSO4s+2NaCl(aq)

    In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate of barium sulphate is formed along with the sodium chloride.

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  2. Oxidation - When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation. 2Cu + O2  --> 2CuO In this reaction copper gains oxygen and hence is oxidized. CuO  +  H2  --> Cu  +  H2O In the above reaction hydroRead more

    Oxidation – When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation.

    2Cu + O2  –> 2CuO

    In this reaction copper gains oxygen and hence is oxidized.

    CuO  +  H2  –> Cu  +  H2O
    In the above reaction hydrogen gains oxygen, and hence oxidized.
    Reduction – If a substance loses oxygen or gains hydrogen during a reaction, it is that the substance is reduced. This phenomenon is called reduction.
    ZnO + C Zn + CO

    In this reaction zinc loses oxygen, and hence called is reduced.
    MnO2+4HClMnCl2+2H2O+Cl2

    In this reaction Mangnese dioxide loses oxygen and hence is called reduced.

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  3. Copper is a brown coloured shiny element, when heated in air, it becomes black in colour. 2Cu+O2→2CuO Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.

    Copper is a brown coloured shiny element, when heated in air, it becomes black in colour.
    2Cu+O22CuO

    Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.

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  4. When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.

    When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.

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  5. When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.

    When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.

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