Chemistry

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Option (iii)

2I^- + 2H⁺ + H₂O₂ → I₂+ 2H₂O

As the oxidation state of iodine changes from -1 to 0, this shows peroxide is oxidising in nature.

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Ans: The charged colloidal particles start moving towards oppositely charged electrodes.

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Ans: The colloidal impurities present in water get coagulated by added alum, thus making water potable.

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Ans: It is a 4% solution of nitrocellulose in a mixture of alcohol and ether.

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Option (ii)

BaO₂ -8H₂O

Hydrogen peroxide is produced by acidifying barium peroxide and eliminating excess water by evaporation under low pressure.

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Ans: Ice creams are emulsions which get stabilised by emulsifying agents like gelatin.

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Ans: Clouds are colloidal in nature and carry charge. Spray of silver iodide, an electrolyte, results in coagulation leading to rain.

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Option (ii)

An oxidizing agent in (A) and reducing agent in (B)

H₂O₂ acts as an oxidising agent in A as it oxidized iodine from -1 to 0, while in B it acts as reducing agent as it reduced chlorine from +1 to -1

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Ans: Gold sol is a lyophobic sol. Addition of gelatin stabilises the gold sol.

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Ans: At lower concentration soap forms a normal electrolytic solution with water. After a certain concentration called critical micelle concentration, colloidal solution is formed.