Chemistry

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Ans: Medicines are more effective in the colloidal form because of large surface area and are easily assimilated in this form.

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Option (ii)

I₂ + H₂O₂ + 2OH^–→ 2I^-+ 2H₂O + O₂

As iodine is reduced from 0 to -1.

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Ans: The emulsifying agent forms an interfacial layer between suspended particles and the dispersion medium thereby stabilising the emulsion.

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Ans: Positively charged sol of hydrated ferric oxide is formed and on adding excess of NaCl, negatively charged chloride ions coagulate the positively charged sol of hydrated ferric oxide.

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Ans: Unbalanced bombardment of the particles of dispersed phase by molecules of dispersion medium causes brownian motion. This stabilises the sol.

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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.