The existance of two or more forms of the same element in the same physical state is known as
отговор
(A)
allotropy
2
When an atom gains an electron, it becomes
отговор
(B)
negatively charged
3
The alkali metals exhibit similar chemical properties because
отговор
(B)
they have the same number of vallence electrons
4
What is the likely formula of compound formed between element M in group two and element X in group seven?
отговор
(D)
MX2
5
''Equal volumes of all gases at the same temperature and pressure contain the same number of molecules'' is an expression of
отговор
(C)
Avogadro's Law
6
What volume of carbon (lV) oxide is produced at s.t.p. when 2.5g of CaCO3 reacts with excess acid according to the following equation? CaCO3 + 2HCI → CaCI2 +H2O + CO2 [CaCO3 = 100; molar volume of a gas at s.t.p = 22.4dm3]
отговор
(D)
0.56dm3
7
A solution of pH 7 is
отговор
(B)
neutral
8
Which of the following equations represents a neutralization reaction?
отговор
(C)
H2SO4 + KOH → KHSO4 + H2 O
9
Amphoteric oxides are oxides which
отговор
(D)
react with acids alkalis
10
The following acids are monobasic except
отговор
(D)
tetraoxophosphorus (V) acid
11
An arrangement of two different metals in aqueous solutions of their salts to produce an electronic current is known as
отговор
(A)
electrochemical cell
12
In which of the following compounds is the oxidation number of nitrogen equal to + 3?
отговор
(D)
HNO2
13
Which of the following statements is not correct about electrolysis?
отговор
(A)
Reduction occurs at the anode
14
Which of the following is not correct about a catalyst? It
отговор
(C)
can start a chemical rection which will normally not take place
15
The rate of production of hydrogen gas from the reaction between zinc granules and hydrochloric acid can be increased by
отговор
(B)
using zinc powder instead of zinc granules
16
What does X represent in the following equation? H 2(g) + 1/2O2(g) → H2O (l); ∆H = xKJ.
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(E)
Enthalpy of formation
17
If the third member of a homologous series is C3H8, the fifth member will be
отговор
(E)
C5H12
18
Which of the following exhibits resonance?
отговор
(A)
Benzene
19
On exposing palm wine to air for some days, it becomes sour owing to the conversion of
отговор
(C)
ethanol to ethanoic acid
20
When acidified KMnO4 solution is decolorised by ethene, the gas acts as
отговор
(C)
a reducing agent
21
What amount of hydrogen will be required for complete hydrogenation of one mole of pent-3-yne?
отговор
(B)
2 moles
22
When excess carbon (lV) oxide is passed into lime water, the turbidity produced initially disappears due to the formation of
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(C)
calcium hydrogentrioxocarbonate (IV)
23
Which of the following is a disaccharide?
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(D)
sucrose
24
Use this following information to answer this question. Compound X was boiled with concentrated hydrochloric acid for a long time. One of the products was found to be a sugar. Compound X was probably
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(D)
cellulose
25
Use this following information to answer this question. Compound X was boiled with concentrated hydrochloric acid for a long time. One of the products was found to be a sugar. What type of reaction was involved between compound X and concentrated hydrochloric acid?
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(C)
Hydrolysis
26
The component of air that can be removed by alkaline pyrogallol solution is
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(A)
oxygen
27
During water treatment for town supply, water is passed through layers of send beds in order to
отговор
(B)
filter the water
28
The cleansing action of soap in hard water is not satisfactory because soap
отговор
(A)
forms insoluble calcium and magnesium salts
29
What is the role of MnO2 in the reaction represented by the following equation?MnO2 + 4HCI2 + CI2 + 2H2O
отговор
(B)
Oxidizing agent
30
Nitrogen is prepared on a large scale by the
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(A)
fractional distillation of liquefied air
31
Ammonia gas is suitable for performing the 'Fountain' experiment because the gas is
отговор
(E)
very soluble in water
32
Which of the following metals will be the most suitable for use where lightness and resistance to corrosion are of importance?
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(E)
Aluminium
33
What amount of copper is deposited when 13.0g of zinc reacts with excess copper (ll) tetraoxosulphate (IV) solution according to the following equation? Zn (s) + CuSO4(aq) → ZnSO4(aq) + Cu (s) [Cu =63,5, Zn = 65]
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(B)
0.2mole
34
The products formed when sodium hydrogen trioxocarbonate (IV) is heated strongly are
отговор
(E)
sodium trioxocarbonate (IV) carbon (IV) oxide and steam
35
The following are properties of transition metals except
