Class 11th

14.33 The pollutant responsible for Bhopal gas tragedy was
(a) Ammonia (b) Methyl isocyanate (c) Nitrous oxide (d) Mustard gas

3.51. State the Modern Periodic Law.

14.32 The main constituents of air are 

(a) N₂ and O₂ (b) SO₂ and CO₂ (c) CO and CO₂  (d) none of the above

MCQs

14.31 . Which of the following statements is incorrect?

(a) The atmosphere that surrounds the earth isnot of the same thickness at all heights. 

(b) The lowest regionof atmosphere in which the human beingsalong with other organisms live is calledtroposphere.

(c) Below the troposphere,between 10 and 50 km above sea level lies stratosphere.

(d) Troposphere is a turbulent,

dusty zone containing air, much water vapour

and clouds.

14.28 Assertion: Tetra chlroroethene was earlier used as solvent for dry cleaning, which now a days are discontinued.

Reason: Chlorine gas was used earlier for bleaching

14.27 Assertion: CO is a colourless and odourless gas, highly poisonous to living beings.

Reason: It is produced as a result of incomplete combustion of carbon and is mainly released into the air by automobile exhaust.

3.47. Mendeleev’s series are

(a) Families

(b) Groups

(c) Periods

(d) None

13.25. Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms? Illustrate your answer by taking one example.

3.46. Choose the incorrect statement

(a) In a triad, the atomic mass of the middle element is the mean of the atomic masses of the first and third elements.

(b) Electronegativity refers to the tendency of atom so share electrons with another atom.

(c) Number of elements in each period is twice the number of atomic orbitals available in the energy level that is being filled.

(d) According to Mendeleev, periodic properties of elements are a function of their atomic masses.

13.24. Suggest the name of a Lewis acid other than anhydrous aluminium chloride which can be used during ethylation of benzene.