CBSE Class 12 Chemistry - Surface Chemistry VBQs Based on CBSE and NCERT guidelines. Value based questions are now being given in exams to promote morals and values in students, Students should read and understand the following VBQs to get better understanding and score good marks in exams
Q1) Kala-azar is a disease caused by mosquito (protozoa) that results in irregular fever enlargement of spleen and hemorrhages that are generally fatal.
(1) What is the treatment of Kala-azar?
(2) Is colloidal antimony, lyophilic or lyophobic colloid?
(3) Is colloidal antimony, multimolecular, macromolecular or associated colloid?
(4) How can we prevent us from fever caused by mosquito?
Ans.(i) colloidal antimony.
(iii) it is lyophobic colloid.
(iii) it is multimolecular colloid.
(iv) we should use mosquito repellant and do not allow stagnant water in coolers, overhead tanks, etc.
Q2) Surface chemistry deals with phenomenon that occurs at all the surface or interfaces. Many important phenomenon- corrosion, electrode process, heterogeneous catalysis, dissociation,adsorption,crystallisation occur at the interfaces.
(1) Why do we use charcoal, in gas marks, in coal mines?
(2) How is animal charcoal, used in the decolourisation of sugar?
(3) What is the use of silica gel which is given along with camera and other electronic equipments?
(4) There is safety lamp in coal mines. What is its purpose?
Ans. (i) it absorbs poisnous gases to large extent and not oxygen which is used for breathing.
(ii) it absorbs the undesirable colours from aqueous solution of sugar, we get colourless sugar.
(iii) silica gel absorbs water molecules on it surface which may spoil the equipment.
(iv) whenever there is excess of carbon monoxide gas, the colour of flame becomes blue and coal mine workers are asked to come out because carbon monoxide gas may lead to death.
Please refer to the link below for CBSE Class 12 Chemistry - Surface Chemistry VBQs