The atoms of four elements are represented as 20Q, 16R, 10S and 8T Which of the elements would be unreactive?
Trả lời
(C)
S
2
Chlorine atom forms \(Cl^{-}\) by
Trả lời
(D)
Gaining one electron
3
An element Z has a combining power of 3. Which of the following formulae is correct of its compounds?
Trả lời
(C)
Z 2O 3
4
Electrovalent compounds are characterized by
Trả lời
(C)
high melting point
5
The type of chemical bond that exists between potassium and oxygen in potassium oxide is
Trả lời
(A)
ionic
6
Which of the following contains co-ordinate covalent bond?
Trả lời
(C)
NH4
7
Elactrostatic force of attraction between sodium ion and halide ion is greatest in
Trả lời
(C)
NaF
8
Which of the following non-metals reacts most readily with metals?
Trả lời
(B)
Chlorine
9
A radioactive solid is best stored
Trả lời
(D)
in a box lined with lead
10
What is the shape of a molecule of CCI4?
Trả lời
(B)
Tetrahedral
11
What are the values of x and y in the following equation? \(^{234}_{90}\)Th → \(^y_x\)Pa + ß- particle
Trả lời
(A)
91
234
12
Which of the following increases as boiling water changes to steam?
Trả lời
(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]
Trả lời
(D)
64g mol -1
14
Which of the following gases is colourless, odourless and soluble in potassium hydroxide solution?
Trả lời
(D)
CO2
15
The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is
Trả lời
(C)
carbon (IV) oxide
16
If a solution has a pH of 2, it can be concluded that it
Trả lời
(D)
will produce effervescence with magnesium ribbon
17
Which of the following salts is stable to heat?
Trả lời
(A)
K2CO3
18
Which of the following compounds dissolves in water to give an alkaline solution?
Trả lời
(D)
Potassium oxide
19
Which of the following salts is an acid salt?
Trả lời
(C)
KHSO4
20
What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3?
Trả lời
(A)
Redox reaction
21
Chemical equilibrium is attained when
Trả lời
(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
Trả lời
(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
Trả lời
(B)
smaller surface area
24
Which of the following will displace copper from a solution of copper (ll) salt?
Trả lời
(B)
Magnesium
25
What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O
Trả lời
(B)
6
26
In which of the following is the oxidation number of sulphur equal to -2?
Trả lời
(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 ?
Trả lời
(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
Trả lời
(A)
contains more ions
29
Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes?
Trả lời
(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?
Trả lời
(C)
Do a chromatogram of the colouring extract
31
2 moles of hydrogen gas will react completely with one mole of....
Trả lời
(D)
CH≡C-CH2-CH3
32
C8H18 will undergo the following reactions except
Trả lời
(D)
addition
33
Which of the following is correct about both compounds shown below? CH3CH 2CH2OH;CH 3
CH 2CH(OH)CH3
Trả lời
(C)
Their general molecular formula is the same
34
Which of the following needs to be hydrolyzed before it shows reducing property?
Trả lời
(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
Trả lời
(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
Trả lời
(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
Trả lời
(C)
zinc hydroxide is amphoteric
38
Which of the following on burning in air contributes to acid rain?
Trả lời
(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
