Oxidation Reduction and Chemical Reaction

Oxidation Reduction and Chemical Reaction
Oxidation Reduction and Chemical Reaction
1. Change of water into the vapour is
called [UPPSC (Pre) 1992]
(a) natural (b) physical
(c) chemical (d) biology
2. An example of physical change
[BPSC (Pre) 1992]
(a) blackening of silverware.
(b) burning of candle.
(c) making of curd from milk.
(d) dissolving of sugar in water.
3. Which one among the following is not a
chemical change? [NDA/NA 2013]
(a) Curdling of milk
(b) Ripening of fruit
(c) Evaporation of water
(d) Burning of coal
4. Which of the following is an example of
chemical change?
[RAS/RTS (Pre) 2003]
(a) Dispersion of white light into the light
of 7 colours when passed through a
prism.
(b) Softening of vegetables when
cooked.
(c) Wet soil lump, when dried, gets fragile.
(d) Dissolving of salt in water.
Oxidation Reduction and Chemical Reaction
5. Statement I Physical change in matter
bring change in its composition and
nature.
Statement II Physical change involves
interconversion of states and colour.
Codes
(a) Both the statements are individually
true and statement II is the correct
explanation of statement I
(b) Both the statements are individually
true, but statement II is not the
correct explanation of statement I
(c) Statements I is true, but statement II
is false
(d) Statements I is false, but statement II
is true
6. Assertion (A) A chemical reaction
becomes faster at a higher
temperature.
Reason (R) At higher temperature,
molecular motion becomes more
rapid. [IAS (Pre) 2001]
Codes
(a) Both A and R are true and R is the
correct explanation of A
(b) Both A and R are true, but R is not
the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
7. Consider the following statements.
I. The freezing of water into ice is a
chemical change.
II. The changes occur in the internal
molecular composition, is a chemical
change.
III. A new substance is obtained in a
chemical change.
IV. The change in shape, size and state
is chemical change.
Which of the statements given above
is/are correct?
(a) I and II
(b) II and III
(c) I, II and III
(d) I and IV
8. Which of the following is/are the
examples of chemical change?
I. Crystallisation of sodium chloride
II. Melting of ice
III. Souring of milk
Oxidation Reduction and Chemical Reaction
Select the correct answer using the
codes given below.
(a) I and II only
(b) Only III
(c) I, II and III
(d) None of the above
9. In a reaction, the concentration of
reactants is equal to the concentration
of products. This state of a reaction is
called as
(a) reversible reaction
(b) chemical equilibrium
(c) irreversible reaction
(d) forward reaction
10. What is the role of positive catalyst in a
chemical reaction? [CDS 2013]
(a) It increases the rate of reaction.
(b) It decreases the rate of reaction.
(c) It increases the yield of products.
(d) It provides better purity of the
products.
11. Solubility of calcium oxides in water
increases on lowering the temperature.
Thus, dissolution process is
(a) endothermic
(b) exothermic
(c) non-thermic
(d) cannot be decided
12. Corrosion is the oxidative deterioration
of a metal, such as tarnishing of silver,
rusting of iron and development of a
green coating on copper and bronze.
Corrosion is an example of
(a) fast reaction
(b) slow reaction
(c) homogeneous reaction
(d) heterogeneous reaction