Surface Chemistry

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 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 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.

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

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

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

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

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

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