The phenomenon observed when dust particles collide randomly in a beam of sunlight is known as?
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(A)
Tyndal effect
2
The mass number of an element is the sum of its
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(C)
protons and neutrons
3
How many unpaired electrons are there in an atom of an element with the following electronic configuration? 1s22s22p6
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(A)
o
4
Radon is used as a tracer in medical research because it
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(B)
is radioactive
5
What is the most probable group of an element which is a soft, silvery white solid and reacts violently with water?
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(B)
Group 1
6
In linear molecules, the bond angle is
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(E)
180o
7
A sodium atom and a sodium ion have the same
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(A)
number of neutrons
8
If the atomic number of an element X is 11 and that of nitrogen is 7, the most likely formula of the nitride of X is
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(A)
X3N
9
An increase in the pressure of a gas results in a decrease in its
Răspuns
(C)
volume
10
A given volume of methane diffuses in 20 seconds. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions? [CH\(_4\) = 16; SO\(_2\) = 64]
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(C)
40 seconds
11
An acid is a substance which in the presence of water produces
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(D)
hydroxonium ions
12
Which of the following is a general method of preparing acids?
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(C)
Reaction between an anhydride and water
13
Which of the following is a general method of preparing acids?
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(D)
Reaction between an anhydride and water
14
The loss of molecules of water of crystallization to the atmosphere by some crystalline salts is known as
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(A)
efflorescence
15
Which of the following ions will migrate to the cathode during electrolysis?
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(A)
Zinc ions
16
What quantity of electrons (in mole) is lost when one mole of iron (ll) ions is oxidized to iron (lll) ions?
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(E)
1 mole
17
The common feature of reactions at the anode is that
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(B)
oxidation is involved
18
From the following equations, what is the order of decreasing reactivity of X, Y and Z? Y (s) + X2+(aq) → Y2+(aq) + X(s) X(s) + Z2+(aq) → X2+(aq) + Z(s)
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(B)
Y > X > Z
19
What is the value of x in the following equation? MnO- 4 + 4H+ + xe- → MnO 2 + 2H2O
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(B)
3
20
If the value of ∆H for a reaction is negative, it means that the reaction is
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(B)
exothermic
21
How much heat will be liberated if 8g of hydrogen burns in excess oxygen according to the following equation? 2H2 + O2→ 2H2O,∆H = -571.7KJ (H = 1)
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(C)
1143.4KJ
22
The position of equilibrium in a reversible reaction is affected by
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(B)
change in concentration of the reactants
23
Separation of mixture of solids by physical methods can be based on differences in the following except
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(D)
molar mass
24
Ethene undergoes mainly addition reactions because it is
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(C)
unsaturated
25
The reaction between alkanoic acids and alkanols in the presence of a mineral acid is known as
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(D)
esterification
26
Which of the following is the relative molecular mass of a compound which has empirical formula CH\(_2\)O? (H = 1; C = 12; O = 16)
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(D)
180
27
The by-product of the fermentation of sugar to ethanol is
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(E)
carbon (lV) oxide
28
Alkanes react with the halogens mainly by
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(E)
substitution
29
Which of the following is used widely in the manufacture of flavours and perfumes?
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(A)
Alkanoates
30
The use of diamond in abrasives is due ti its
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(D)
hardness
31
Which of the substance lettered P to V in the equation below would be left on the filter paper if the reaction mixture were filtered? P (aq) + Q(aq) → V(s) + R(aq) + T(g)
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(C)
V
32
When chlorine is added to slaked lime, the product obtained is
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(A)
bleaching powder
33
Which of the following when heated strongly in air will leave a metal as residue?
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(C)
Silver trioxonitrate (V)
34
Which of the following is used as water softener?
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(A)
Na2CO3.10H2O
35
The following oxides react with both acids and bases to form salts except
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(E)
carbon (Iv) oxide
36
Which of the following metals is not extracted by electrolysis ?
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(A)
lron
37
Which of the following is an ore of aluminium?
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(D)
Bauxite
38
Lead and tin are the components of
Răspuns
(E)
soft solder
39
An atom 17 protons, 17 electrons and 18 neutrons has a mass number of
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(D)
35
40
If an element R belongs to the same group as sodium, an aqueous solution of ROH will
Răspuns
(D)
have pH greater than 7
41
Element X, with electronic configuration 2, 8, 2 and element Y with electronic configuration 2, 8, 7 are like to combine by
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(C)
electrovalent bonding
42
The valence electrons of element 12Mg are in the
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(E)
3s orbital
43
Which of the following statements is correct about sodium chloride in the solid state?
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(A)
it exists as aggregates of ions
44
Which of the following Group 1 elements has the highest ionization energy?
