WAEC - Chemistry (1992)

1
When steam is passed over white-hot coke, the products are
Answer
(B)
carbon (II) oxide and hydrogen
2
The maximum number of electrons that can accommodated in the shell having the principal quantum number 3 is
Answer
(D)
18
3
Methanol is obtained from wood by
Answer
(E)
destructive distillation
4
Study carefully the reaction represented by the equation below. 2H2O 2(l) → O 2(g) + 2H2O(l). Which of the following will not reaction increase the reaction rate?
Answer
(D)
Adding water to the reactant
5
Which of the following processes is a physical reaction?
Answer
(C)
Allotropic change
6
If the volume of a given mass of gas at 298 K and pressure of 205.2 x 10\(^3\) Nm\(^{-2}\) is 2.12dm\(^3\), what is volume of the gas at s.t.p? (Standard pressure = 101.3 x 10\(^3\) Nm\(^{-2}\), Standard temperature = 273K)
Answer
(D)
3.93dm3
7
The following acids are monobasic except
Answer
(C)
ethanedioic acid
8
The reactions ethyne are mainly
Answer
(B)
addition reactions
9
When air is passed through potash and then pyrogallol, the components are noble gases,
Answer
(C)
nitrogen and water vapour
10
The halide used widely in photography is
Answer
(C)
silver bromide
11
The scum formed when soap is mixed with hard water could be
Answer
(A)
calcium trioxocarbonate (IV)
12
What is the quantity of electricity produced when a current of 0.5A is passed for 5 hours 45 mins? (1F = 96500C)
Answer
(A)
0. 11F
13
''The rate a reaction is proportional to the number of effective collisions occurring per second between the reactants''. This statement is associated with the
Answer
(D)
collision theory
14
What is the following compounds will not decompose when heated strongly ?
Answer
(B)
K2CO3
15
What is the change in the oxidation number of phosphorus in the the reaction represented by the following equation? 4P (s) + 5O(2)(g) → 2P2O5(g)
Answer
(B)
0 to 5
16
When iron rusts, it undergoes
Answer
(D)
redox reaction
17
Consider the compounds represented by the following general formula: X2SO4 Y2(SO4)3, 24H2OX and Y could respectively be
Answer
(A)
K and AI
18
Which of the following involves the decomposition enzymic action?
Answer
(B)
Fermentation
19
The following salts are readily soluble in water except
Answer
(D)
CuCO3
20
When sucrose is warmed with Fehling's solution
Answer
(D)
there is no precipitate
21
Which of the following gases will have the highest rate of diffusion under the same conditions? (H = 1, C =12, O = 16, S = 32, CI = 35.5)
Answer
(A)
O2
22
The formula (CH3),3 COH is that of a
Answer
(C)
tertiary alkanol
23
What is the number of oxygen atoms in 32g of the gas? (O = 16, L = 6.0 X 10\(^{23}\) mol\(^{-1}\))
Answer
(B)
6.0 X 1023
24
Which of the following compounds is not correct about the reaction of sodium material for the manufacture of plastics?
Answer
(B)
Ethane
25
The energy required to remove the most loosely bound electron from an atom in the gaseous state is known as the
Answer
(B)
ionization energy
26
Vulcanization of rubber
Answer
(D)
hardnes the rubber through cross-linkage
27
If a reaction is said to be exothermic, which of the following statements is a correct deduction from the information?
Answer
(A)
the reaction vessel gets hotter as the reaction proceeds
28
If a reaction is said to be exothermic, which of the following statements is a correct deduction from the information?
Answer
(A)
the reaction vessel gets hotter as the reaction proceeds
29
Which of the following statement is not correct about esterification?
Answer
(C)
it is similar to hydrolysis
30
Which of the following statements is not correct? The 4s orbital
Answer
(B)
is of higher energy than the 3d orbital
31
Which of the following pH values is likely to be that of a slightly alkaline solution?
Answer
(D)
8
32
Which of the following minerals contains flurine as one of its constituent elements?
Answer
(A)
Cryolite
33
The product of the reaction between propanoic acid and ethanol is
Answer
(E)
ethylpropanoate
34
Which of the following groups contains entirely linear molecules?
Answer
(D)
CO2H2N2
35
What is the value of n in the following equation? XO-4 +8H + + ne- → X2 + + 4H2O
Answer
(D)
5