Monday 9 March 2015

CHEMISTRY SECTION I



            1.  Why do two ice blocks join to form one block when pressed together?

(a)    Melting point  of ice is lowered with increase in pressure
(b)   Melting point of ice increases with increase in pressure
(c)    Melting point of ice remains unchanged with increase in pressure
(d)   Melting point of ice is 0˚C

            2. Aqua-regia used by alchemists to separate silver and gold is a mixture of

(a)    Hydrochloric and (concentrated) and nitric acid (concentrated)
(b)   Hydrochloric acid (concentrated) and sulphuric acid (concentrated)
(c)    Nitric acid (concentrated ) and sulphuric acid (concentrated)
(d)   Hydrochloric acid (dilute) and sulphuric and (dilute)

           3. Consider the following statements.

1.       Marble is a constituent of tooth paste.
2.       Gypsum is used for the manufacture of ammonium sulphate.

Which of the statements given above is/ are correct?

(a)    Only 1
(b)   Only 2
(c)    Both 1 and 2
(d)   Neither 1 nor 2

            4. Consider the following statements.

1.        Glycerol is used in explosives.
2.       Detergents are made from hydrocarbons obtained from coal or petroleum.
3.       Sodium perborate is a mild bleaching agent.
4.       Methanol I sued for making synthetic fibres.

Which of the statements given above are correct?

(a)    1,  2,  3 and 4
(b)   1,  2 and 3
(c)    2,  3  and 4
(d)   1  and 4

        5.  A pale blue gas with a fish-like odour restores the colour of a blackened lead painting. The gas is also used as rocket fuel. It is

(a)    Oxygen
(b)   Ammonia
(c)    Sulphur dioxide
(d)   Ozone

          6. Calcium carbonate is naturally available as limestone and can also be synthesized from quicklime. It is seen that the compositions of the elements in both the natural and synthetic calcium carbonate are same. The validity of which one among the following laws is confirmed  by this observation?

(a)    Law of conservation of mass
(b)   Law of definite proportion
(c)    Law of multiple proportion
(d)   Avogadro’s law
          7.  The Bleaching action of chlorine occurs in the presence of

(a)    Moisture
(b)   Sunlight
(c)    pure oxygen
(d)   Pure sulphur dioxide

          8. Which one among the following statements regarding the properties of mixtures and compounds is not correct?

(a)    A mixture shows the properties of its constituents but the properties of a compound are entirely different from its constituents
(b)   A mixture may be homogeneous or heterogeneous but a compound is a homogeneous substance
(c)    The constituents of a mixture can be separated by physical methods but those of a compound cannot be separated by physical methods
(d)   Energy is either absorbed or evolved during the preparation of  a mixture but not in the preparation of a compound
        9.  Shallow lake with rich organic products are called

(a)    Heterotrophic
(b)   Eutrophic
(c)    Mestrophic
(d)   Oligotrophic

          10.     An oxidizing agent is a substance which

                 (a)    Increases the oxidation number of an element is a given substance
                 (b)   Decreases the oxidation number of an element is a given substance
                 (c)    Is oxidized itself in an oxidation reduction reaction
                (d)   Loses electrons in an oxidation reduction reaction

Answer:

1.       A
2.       A
3.       C
4.       B
5.       B
6.       B
7.       A
8.       D
9.       B
10.   A


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