The atoms of four elements are represented as 20Q, 16R, 10S and 8T Which of the elements would be unreactive?
Відповідь
(C)
S
2
Chlorine atom forms \(Cl^{-}\) by
Відповідь
(D)
Gaining one electron
3
An element Z has a combining power of 3. Which of the following formulae is correct of its compounds?
Відповідь
(C)
Z 2O 3
4
Electrovalent compounds are characterized by
Відповідь
(C)
high melting point
5
The type of chemical bond that exists between potassium and oxygen in potassium oxide is
Відповідь
(A)
ionic
6
Which of the following contains co-ordinate covalent bond?
Відповідь
(C)
NH4
7
Elactrostatic force of attraction between sodium ion and halide ion is greatest in
Відповідь
(C)
NaF
8
Which of the following non-metals reacts most readily with metals?
Відповідь
(B)
Chlorine
9
A radioactive solid is best stored
Відповідь
(D)
in a box lined with lead
10
What is the shape of a molecule of CCI4?
Відповідь
(B)
Tetrahedral
11
What are the values of x and y in the following equation? \(^{234}_{90}\)Th → \(^y_x\)Pa + ß- particle
Відповідь
(A)
91
234
12
Which of the following increases as boiling water changes to steam?
Відповідь
(B)
degree of disorder in the system
13
9.60 g of a gas X occupies the same volume at 0.30 g of hydrogen under the same conditions. Calculate the molar mass of X [H = 1]
Відповідь
(D)
64g mol -1
14
Which of the following gases is colourless, odourless and soluble in potassium hydroxide solution?
Відповідь
(D)
CO2
15
The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is
Відповідь
(C)
carbon (IV) oxide
16
If a solution has a pH of 2, it can be concluded that it
Відповідь
(D)
will produce effervescence with magnesium ribbon
17
Which of the following salts is stable to heat?
Відповідь
(A)
K2CO3
18
Which of the following compounds dissolves in water to give an alkaline solution?
Відповідь
(D)
Potassium oxide
19
Which of the following salts is an acid salt?
Відповідь
(C)
KHSO4
20
What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3?
Відповідь
(A)
Redox reaction
21
Chemical equilibrium is attained when
Відповідь
(C)
concentrations of the reactants and products remain constant
22
What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO2 + O2 ⇌ 2SO3; ∆H = - xKJmol-1
Відповідь
(D)
Reduces the time for attainment of equilibrium
23
A finely divided form of a metal burns more readily in air than the rod form because the rod has
Відповідь
(B)
smaller surface area
24
Which of the following will displace copper from a solution of copper (ll) salt?
Відповідь
(B)
Magnesium
25
What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O
Відповідь
(B)
6
26
In which of the following is the oxidation number of sulphur equal to -2?
Відповідь
(B)
H2S
27
An iron nail placed in a solution copper (ll) tetraoxosulphate (VI) is soon covered with a deposit of copper. Which of the following equations represents the reactions ?
Відповідь
(D)
Fe(s) + Cu2+ → Fe2+(aq) + Cu(s)
28
0.10 mol dm-3 NaCI conducts electricity better than 0.10 mol dm-3 CH3COOH because the solution of NaCI
Відповідь
(A)
contains more ions
29
Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes?
Відповідь
(A)
The cathode becomes coated with copper
30
Which of the following procedures is suitable for identifying the food colouring added to a pastry sample?
Відповідь
(C)
Do a chromatogram of the colouring extract
31
2 moles of hydrogen gas will react completely with one mole of....
Відповідь
(D)
CH≡C-CH2-CH3
32
C8H18 will undergo the following reactions except
Відповідь
(D)
addition
33
Which of the following is correct about both compounds shown below? CH3CH 2CH2OH;CH 3
CH 2CH(OH)CH3
Відповідь
(C)
Their general molecular formula is the same
34
Which of the following needs to be hydrolyzed before it shows reducing property?
Відповідь
(C)
Sucrose
35
Two-organic substances are labelled K and L if K gave a blue-black colour with iodine solution and L gave a deep red precipitate with Million's reagent, it can be concluded that
Відповідь
(A)
K is a carbohydrate and L is a protein
36
A colourless, odourless liquid T, gives effervescence with sodium trioxocarbonate (IV) and a white precipitate with silver trioxonitrate (V) solution T is most probably
Відповідь
(D)
dilute hydrochloric acid
37
When sodium hydroxide solution is added to a solution of zinc salt, the white precipitate formed re-dissolves in excess sodium hydroxide because
Відповідь
(C)
zinc hydroxide is amphoteric
38
Which of the following on burning in air contributes to acid rain?
Відповідь
(A)
Sulphur
39
If 20 cm3 of distilled water is added to 80 cm3 of 0.50 mol dm-3 hydrochloric acid, the concentration of the acid will change to
