1. ANSWER: [B] Explanation: When CO₂ is first passed through lime water, Ca(OH)₂ reacts to form insoluble CaCO₃, which makes the solution milky. On passing excess CO₂, the CaCO₃ dissolves forming soluble Ca(HCO₃)₂, causing the milkiness to disappear.

    ANSWER: [B]

    Explanation: When CO₂ is first passed through lime water, Ca(OH)₂ reacts to form insoluble CaCO₃, which makes the solution milky. On passing excess CO₂, the CaCO₃ dissolves forming soluble Ca(HCO₃)₂, causing the milkiness to disappear.

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  2. The correct answer is [C]. The reaction that converts alkenes into alkanes is called hydrogenation. In this process, hydrogen gas (H₂) is added to the carbon–carbon double bond of the alkene, converting it into a single bond, thereby forming an alkane. For hydrogenation to occur, specific conditionsRead more

    The correct answer is [C]. The reaction that converts alkenes into alkanes is called hydrogenation. In this process, hydrogen gas (H₂) is added to the carbon–carbon double bond of the alkene, converting it into a single bond, thereby forming an alkane. For hydrogenation to occur, specific conditions are required: a metallic catalyst, usually nickel (Ni), must be present to speed up the reaction, and the reaction temperature should be maintained around 423 K. This process is widely used in the food and chemical industries.

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  3. ANSWER: [D] Explanation: The chemical reaction between dilute hydrochloric acid and granulated zinc is represented as: Zn + 2HCl → ZnCl₂ + H₂ ↑ The product zinc chloride, does not turn the reaction milky. Hydrogen gas evolved is colourless and odourless and released by the formation of bubbles. HencRead more

    ANSWER: [D]

    Explanation: The chemical reaction between dilute hydrochloric acid and granulated zinc is represented as:

    Zn + 2HCl → ZnCl₂ + H₂ ↑

    The product zinc chloride, does not turn the reaction milky. Hydrogen gas evolved is colourless and odourless and released by the formation of bubbles. Hence, your answer will be option [D].

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  4. ANSWER: [B] Explanation: As detergent are basic in nature, the concentration of Hydroxide ions will be high and concentration of hydronium Ions will be less. [Note: When bases are dissolved in water they dissociate into Hydroxide ions]

    ANSWER: [B]

    Explanation: As detergent are basic in nature, the concentration of Hydroxide ions will be high and concentration of hydronium Ions will be less.

    [Note: When bases are dissolved in water they dissociate into Hydroxide ions]

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  5. ANSWER: [D] Explanation: During the preparation of hydrogen chloride gas, the gas is usually passed through the guard tube containing calcium chloride during humid climate, as calcium chloride is a good drying agent and absorbs moisture from the gas.

    ANSWER: [D]

    Explanation: During the preparation of hydrogen chloride gas, the gas is usually passed through the guard tube containing calcium chloride during humid climate, as calcium chloride is a good drying agent and absorbs moisture from the gas.

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