Friday, 29 January 2021

CBSE Class 12 Chemistry - MCQ and Online Tests - Unit 5 - Surface Chemistry

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 5 – Surface Chemistry

Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.


 

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 5 – Surface Chemistry

Question 1.
Shape selective catalysis is a reaction catalysed by
(a) zeolite
(b) enzymes
(c) platinum
(d) Ziegler-Natta catalyst

Answer

Answer: (a) zeolite


Question 2.
The activity of an enzyme becomes ineffective
(a) at low temperature
(b) at atmospheric pressure
(c) at high temperature
(d) in aqueous medium

Answer

Answer: (c) at high temperature


Question 3.
Volume of one mole of any gas at NTP is
(a) 11.2 litre
(b) 22.4 litre
(c) 10.2 litre
(d) 22.8 litre

Answer

Answer: (b) 22.4 litre


Question 4.
Which of the following can adsorb larger volume of hydrogen gas?
(a) Finely divided platinum
(b) Colloidal solution of palladium
(c) Small pieces of palladium
(d) A single metal surface of platinum

Answer

Answer: (b) Colloidal solution of palladium


Question 5.
Which of the following gases present in a polluted area will be adsorbed most easily on the charcoal gas mask?
(a) H2
(b) O3
(c) N2
(d) SO2

Answer

Answer: (d) SO2


Question 6.
A colloidal system is which liquid is dispersed phase and solid is dispersion medium is classified as
(a) gel
(b) sol
(c) emulsion
(d) aerosol

Answer

Answer: (a) gel


Question 7.
Which of the following will not form a colloidal system?
(a) Solid-gas
(b) Liquid-gas
(c) Gas-gas
(d) Gas-liquid

Answer

Answer: (c) Gas-gas


Question 8.
Fog in an example of colloidal system of
(a) liquid in gas
(b) gas in liquid
(c) solid in gas
(d) gas in solid

Answer

Answer: (a) liquid in gas

Question 9.
Tyndall effect confirms the
(a) gravity effect on the sol. particles
(b) light scattering by the sol. particles
(c) heterogeneous nature of sols.
(d) Brownian motion of the sol. particles

Answer

Answer: (c) heterogeneous nature of sols.


Question 10.
Which of the following is not correct for enzyme catalysis?
(a) The enzyme activity is maximum at optimum pH which is between 5-7
(b) Each enzyme is specific for a given reaction
(c) The favourable temperature range of enzyme activity is between 25-37°C
(d) The enzymatic activity is increased in presence of certain substances.called co-enzymes

Answer

Answer: (c) The favourable temperature range of enzyme activity is between 25-37°C


Question 11.
Movement of dispersion medium under the influence of electric field is known as
(a) electrodialysis
(b) electrophoresis
(c) electroosmosis
(d) cataphoresis

Answer

Answer: (c) electroosmosis


Question 12.
Substances which behave as normal electrolytes solution at low concentration and exhibit colloids properties at higher concentration are called
(a) lyophilic colloids
(b) lyophobic colloids
(c) macromolecular colloids
(d) associated colloids

Answer

Answer: (d) associated colloids


Question 13.
Which of the following acts as the best coagulating agent for ferric hydroxide sol?
(a) Potassium ferrocyanide
(b) Potassium chloride
(c) Potassium oxalate
(d) Aluminium chloride

Answer

Answer: (a) Potassium ferrocyanide


Question 14.
The formation of micelles takes place only above
(a) critical temperature
(b) Kraft temperature
(c) inversion temperature
(d) absolute temperature

Answer

Answer: (b) Kraft temperature


Question 15.
The size of colloidal particles ranges between
(a) 10-7 – 10-8 cm
(b) 10-9 – 10-11 cm
(c) 10-4 – 10-7 cm
(d) 10-2 – 10-3 cm

Answer

Answer: (c) 10-4 – 10-7 cm


Question 16.
At CMC (critical micelle concentration) the surface molecules
(a) dissociate
(b) associate
(c) become bigger in size due to adsorption
(d) become smaller in size due to decomposition

Answer

Answer: (b) associate


Question 17.
Presence of traces of arsenious oxide (As2O3) in the reacting gases SO2 and O3 in presence of plantinised asbestos in contact process acts as
(a) catalytic promoter
(b) catalytic poison
(c) dehydrating agent
(d) drying agent

Answer

Answer: (b) catalytic poison


Question 18.
Which of the following is not a method of removing impurities from a colloidal sol?
(a) Electrodialysis
(b) Ultrafiltration
(c) Ultra centrifugation
(d) Distillation

Answer

Answer: (d) Distillation


Question 19.
Which of the following is not a method for coagulation of lyophobic sols?
(a) By electrophoresis
(b) By mixing oppositely charged sols
(c) By adding electrolyte
(d) By adding a protective colloid

Answer

Answer: (d) By adding a protective colloid


Question 20.
Which one of the following is alyophilic colloid?
(a) Milk
(b) Gum
(c) Fog
(d) Blood

Answer

Answer: (b) Gum


Question 21.
The substances which behave as colloidal solutions at higher concentration are called
(a) associated colloids
(b) multimolecular colloids
(c) macromolecular colloids
(d) protective colloids

Answer

Answer: (a) associated colloids


Question 22.
The oxide of nitrogen which acts as a catalyst in lead chamber process is
(a) NO
(b) NO2
(c) N2O4
(d) H2O5

Answer

Answer: (a) NO


Question 23.
Which kind of catalysis can be explained on the basis of adsorption theory ?
(a) Homogeneous catalysis
(b) Heterogeneous catalysis
(c) Negative catalysis
(d) Auto catalysis

Answer

Answer: (b) Heterogeneous catalysis


Question 24.
Why is alum added to water containing suspended impurities?
(a) To make acolloidal solution
(b) To coagulate the suspended impurities
(c) To remove impurities of calcium and magnesium
(d) To protect the colloidal solution from gening precipitated

Answer

Answer: (b) To coagulate the suspended impurities


Question 25.
Which of the following types of metals make the most efficient catalyst?
(a) Alkali metals
(b) Transition metals
(c) Inner transition metals
(d) Alkaline earth metals

Answer

Answer: (b) Transition metals


 

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