Chemistry

This is a Short Answers Type Questions as classified in NCERT Exemplar

Ans: Animal hide is colloidal in nature and has positively charged particles. When it is soaked in tannin which has negatively charged colloidal particles, it results in mutual coagulation taking place.

This is a Short Answers Type Questions as classified in NCERT Exemplar

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

This is a multiple choice answer as classified in NCERT Exemplar

Option (ii)

I₂ + H₂O₂ + 2OH^–→ 2I^-+ 2H₂O + O₂

As iodine is reduced from 0 to -1.

This is a Short Answers Type Questions as classified in NCERT Exemplar

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

This is a Short Answers Type Questions as classified in NCERT Exemplar

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.

This is a Short Answers Type Questions as classified in NCERT Exemplar

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

This is a multiple choice answer as classified in NCERT Exemplar

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.

This is a Short Answers Type Questions as classified in NCERT Exemplar

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

This is a Short Answers Type Questions as classified in NCERT Exemplar

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

This is a Short Answers Type Questions as classified in NCERT Exemplar

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