The formation of a bond between hydrogen and a highly electronegative atom results in
Răspuns
(A)
polarity
7
Which of the elements in the table below would react more readily with chlorine?
Element
Ionization energy (KJ \(mol^{-1} \times 10^{-3}\))
W
12.0
X
21.0
Y
106.0
Z
200.0
Răspuns
(C)
W and X only
8
Which of the following properties does not give evidence of the kinetic theory of matter?
Răspuns
(C)
Polymerization
9
Dilute trioxonitrate (V) acid does not produce hydrogen when it reacts with metals because
Răspuns
(D)
it is a strong oxidizing agent.
10
Which of the following statements is correct?
Răspuns
(D)
An alkane with 49 carbon atoms contains 100 hydrogen atoms
11
A mixture containing two salts of different solubility can be separated by
Răspuns
(B)
crystallization.
12
Species that occur in a reaction pathway but not in the overall reaction are known as
Răspuns
(D)
Intermediates
13
How many moles are there in 3.0 g of \(O_2\)? [O = 16.0]
Răspuns
(B)
0.0930 moles.
14
Which of the following equimolar solutions has the highest conductivity?
Răspuns
(A)
\(H_2SO{_4(aq)}\)
15
The pair of compounds that belongs to the same homologous series is
Răspuns
(A)
\(C_2H_6\) and \(C_4H_{10}\)
16
Which of the following equations does not illustrate correctly one of the reactions of chlorine?
Răspuns
(B)
\(Cl_2 + 2NaF → 2NaCl + F_2\)
17
The salt solution formed firm a reaction between ethanoic acid and sodium hydroxide solution would be
Răspuns
(C)
basic
18
The separation technique that is suitable for separating iodine from tetrachloromethane is
Răspuns
(A)
solvent extraction
19
Consider the following reaction equation:
\(2SO_3(g) → 2SO_2(g) + O_2\)(g)
∆H = +198 kJ/mol
Which of the following statements about the reaction is correct?
Răspuns
(D)
198 kJ of energy is absorbed
20
Arrange the following compounds in decreasing order of their boiling points: \(NH_3\), HF, \(SiH_4\), \(CH_4\)
Răspuns
(A)
HF,\(NH_3\), \(SiH_4\), \(CH_4\)
21
Copper (II) ions are able to participate in co-ordinate covalent bonding because they
Răspuns
(C)
have vacant d-orbital
22
What takes place at the cathode during electrolysis?
Răspuns
(D)
Cations are discharged.
23
Carbon is deposited in the exhaust pipes of cars because of
Răspuns
(B)
incomplete combustion of petrol
24
Which of the following laws or theory cannot be explained by the application of the kinetic theory of gases?
Răspuns
(A)
Dalton's atomic theory
25
How many unpaired electrons are present in \(_{26}Fe^{3+}\)?
Răspuns
(D)
5
26
A consequence of global warming is
Răspuns
(C)
flooding
27
Going down group II in the periodic table normally
Răspuns
(B)
melting point increases
28
The primary component of natural gas
Răspuns
(B)
methane
29
The gas that is less dense than air is
Răspuns
(A)
nitrogen
30
The periodic property that is used to determine whether a covalent molecule is polar or not is
Răspuns
(D)
electronegativity
31
If \(100^3\) of a saturated solution of sodium tetraoxosulphate (VI) at 30° C contains 10.5 g of the salt, what would be its solubility at this temperature? [(\(Na_2SO_4\) = 142]
Răspuns
(B)
0.74 mol dm-3
32
A compound that could be dried by using conc. tetraoxosulphate (VI) acid and not by calcium oxide is likely to be
Răspuns
(D)
an acid anhydride
33
Which of the statements about gases is not correct?
Răspuns
(D)
Gases are highly soluble in water at high temperatures
34
Determine the volume of 0.100 mol of HCl in \(0.250 mol dm^3\) of solution.
Răspuns
(D)
\(400cm^3\)
35
Positive ions in a sea of electrons are found in
Răspuns
(B)
metallic bonds
36
An element X has two isotopes, \(^{65}X_{30}\) and \(^{66}X_{30}\) with relative abundance of 60 % and 40% respectively. The relative atomic mass of X is
Răspuns
(D)
65.40
37
Which of the following statements about the collision theory is correct?
Răspuns
(C)
The rate of reaction is proportional to the number of effective collisions
38
Which of the following elements has its valence electrons in the s-orbital?
Răspuns
(C)
Sodium
39
Petrochemistry is an example of
Răspuns
(A)
applied chemistry
40
The molecule that has a non-polar covalent bond is
Răspuns
(C)
\(Cl_2\)
41
The reduction half equation of the following reaction is:
\(Zn_{(s)} + CuSO_{4(aq)} → ZnSO_{4(aq)} + Cu_{(s)}\)
Răspuns
(C)
\(Cu^{2+}_{(aq)} + 2e^- → Cu_{(s)}\)
42
Why are \(H_2SO_4\) and \(CaCl_2\), not suitable for drying ammonia gas? They
Răspuns
(D)
react with the gas
43
Isoelectronic species have the same number of
Răspuns
(B)
electrons
44
Which of the following gases has the lowest rate of diffusion?
[H=1.0, C=12.0, N = 14.0, O= 16.0]
Răspuns
(D)
Oxygen
45
An example of a crystalline substance that does not possess water of crystallization is
