When sodium chloride and metallic sodium are each dissolved in water
إجابة
(D)
the dissolution of metallic sodium is exothermic
3
The periodic classification of elements is an arrangement of the elements in order of their
إجابة
(D)
Atomic Numbers
4
In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?
إجابة
(E)
50cm3
5
A small quantity of solid ammonium chloride (NH4Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone?
إجابة
(B)
sublimation
6
Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,
إجابة
(D)
Q will form an electrovalent bond with S
7
An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the
إجابة
(A)
law of multiple proportions
8
The oxidation state of chlorine in potassium chlorate is?
إجابة
(D)
+5
9
When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are?
إجابة
(D)
nitrogen and the rare gases
10
When heat is absorbed during a chemical reaction, the reaction is said to be
إجابة
(D)
endothermic
11
When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as
إجابة
(C)
cracking
12
The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore
إجابة
(D)
W is the most acidic solution
13
When each of the nitrates of Potassium, Magnesium and iron is heated,
إجابة
(C)
the nitrates of magnesium and iron give the oxides
14
Which of the following metals cannot replace hydrogen from water or steam?
إجابة
(E)
Copper
15
A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by
إجابة
(D)
adding sodium carbonate
16
During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,
إجابة
(D)
the litmus turns red and oxygen is evolved
17
The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;
إجابة
(C)
esterification
18
The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;
إجابة
(A)
acetic acid and ethene
19
If 30cm\(^3\) of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm\(^3\) of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?
إجابة
(C)
21 sec
20
Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys?
إجابة
(C)
Copper
21
Which of the following gases may not be dried with concentrated sulphuric acid?
إجابة
(E)
NH3
22
Which of the following reactions does not take place in the smelting of iron in a blast furnace?
إجابة
(C)
3\(Fe{(s)} + 2O_{2(g)} → FeO_{4(s)}\)
23
Which of the following is not a member of the homologous series of the paraffins (alkanes)?
إجابة
(E)
C24H48
24
When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called
إجابة
(D)
co-ordinate bond
25
An example of an alcohol is
إجابة
(E)
CH3OH
26
The nucleus of an atom contains
إجابة
(E)
protons and neutrons
27
Hypochlorous acid is used as a bleach because
إجابة
(C)
it is an oxidising agent
28
The normal boiling point of a liquid is defined as?
إجابة
(A)
the temperature at which its vapour pressure equals the atmospheric pressure
29
Which of the following compounds will form a solution if exposed to air?
إجابة
(D)
CaCl2
30
The most common type of chemical reaction which alkanes undergo is
إجابة
(A)
substitution
31
Consider the following exothermic reaction
2SO2(g) + O2(g) ↔ 2SO3(g)
If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then
إجابة
(C)
concentration of SO3 increases
32
If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because
إجابة
(C)
zinc is more electropositive than copper
33
Three solutions contain carbonate, sulphate and sulphide ions respectively. One test that will identify just ONE of them completely is by addition to each of them of
إجابة
(C)
lead nitrate solution
34
Two gas cylinders contain ethylene (ethene) and acetylene respectively. One test which can be used to distinguish between them is by?
إجابة
(C)
passing each gas through silver nitrate solution
35
Consider the following equation H2O + 2Fe2+ + Cl2 ↔ 2Fe3+ + 2Cl- + H2O. Which behaves as an oxidizing agent?
إجابة
(B)
Cl2
36
If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is
إجابة
(E)
Iron (II) chloride
37
Which of the following changes is physical?
إجابة
(D)
Cooling water to obtain ice
38
By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and?
إجابة
(B)
sand
39
In titration involving sodium hydroxide and dilute hydrochloric acid, where would you place the base?
إجابة
(B)
in the conical flask
40
A gas jar was inverted over burning yellow phosphorus floating over water in a beaker. After burning, the water level was found to rise in the gas jar. The water level rises because
إجابة
(C)
oxygen in the gas jar had been used up by burning
41
You are provided with five gas jars containing SO2, CO2, H2, CO and NO respectively. Select a test from A to E which will identify ANY ONE of the gases completely
إجابة
(A)
pass each gas into lime water
42
Which of the following substances would you see as an indicator in the titration of sodium carbonate solution against hydrochloric acid (complete neutralisation)?
إجابة
(C)
Methyl orange
43
Which of the five atoms can be described by the following properties: Relative atomic mass is greater than 30 but less than 40, it has odd atomic number and forms a unipositive ion in solution?
إجابة
(D)
Y
44
A solid X when heated gives off a brown gas. If X is soluble in excess sodium hydroxide solution but insoluble in excess ammonium hydroxide solution, then X is
إجابة
(B)
lead (II) nitrate
45
Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100\(^o\)C, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0\(^o\)C?
