Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
482 views
in Surface Chemistry by (57.3k points)

Give the reasons
(a) Alum purifies drinking water.
(b) A substance can be both colloidal and crystalloid
(c) Sky appears blue.

1 Answer

+1 vote
by (61.1k points)
selected by
 
Best answer

(a) Impure water contains soil particles, bacteria etc. These particles are negatively charged. Alum is added in water to remove them. Al3+ ions present in alum precipitates impurities present in water. Pure water is separated by decantation.
(b) Colloids:
These are not diffused from animal membrane.
Crystalloids:
These are diffused from animal membrane. But the classification of substance given by Grahm was not satisfactory completely, because a specific compound behaves as crystalloids in one solvent and also as colloid in other solvent.
Example:
The aqueous solution of NaCl is crystalloid while it behaves as colloid in benzene.
(c) The wavelength of blue colour is very less hence its scattering is very high. Due to this reason, sky appears as blue.

Related questions

0 votes
1 answer
0 votes
1 answer
0 votes
1 answer
0 votes
1 answer

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...