the constituent of a compound are chemically bound together while those of a mixture are not
2
What is the percentage of sulphur in sulphur (IV) oxide?
پاسخ دهید
(D)
50%
3
A gas X diffuses twice as fast as gas Y. if the relative molecular mass of X is 32, calculate the relative molecular mass of Y.
پاسخ دهید
(A)
128
4
200 cm3 of a gas at 25ºC exerts a pressure of 700 mmHg. Calculate its pressure if its volume increase 350 cm3 at 75ºC.
پاسخ دهید
(C)
467.11 mmHg
5
An element X has electron configuration 1s2 2s2 2p6 3s2 3p5. Which of the following statements is correct about the element?
پاسخ دهید
(D)
lt is a halogen
6
Beryllium and aluminum have similar properties because they?
پاسخ دهید
(D)
are positioned diagonally to each other
7
If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is
پاسخ دهید
(D)
ionic
8
How many protons, neutrons and electrons respectively are present in the element 60/27 Co?
پاسخ دهید
(C)
27, 33, and 27
9
The radio active radiation used in studying the arrangement of particles in giant organic molecules is
پاسخ دهید
(C)
X-rays
10
A silicon -containing ore has 92% 28Si, 5% 29Si and 3% 30Si. Calculate the relative atomic mass of the silicon.
پاسخ دهید
(C)
28.11
11
Water is said to be temporarily hard when it contains
پاسخ دهید
(A)
Ca (HCO3)2 and Mg (HCO3)2 salts
12
On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as
پاسخ دهید
(A)
efflorescence
13
16.55g of lead (ll) trioxonitrate (V) was dissolved in 100g of distilled water at 20oC, calculate the solubility of the solute in moldm-3
[Pb = 207, N = 14, O = 16]
پاسخ دهید
(D)
0.50g
14
The dispersion of a liquid in a liquid medium will give
پاسخ دهید
(A)
an emulsion
15
The major and most effective way of controlling pollution is to
پاسخ دهید
(C)
educate people on the causes and effects of pollution
16
The basicity of CH3COOH is
پاسخ دهید
(B)
1
17
The colour of litmus in a neutral medium is
پاسخ دهید
(A)
purple
18
The mathematical expression of PH is
پاسخ دهید
(B)
log 101/[H 3 O+]
19
Which of the following salts will turn blue litmus red?
پاسخ دهید
(B)
Sodium hydrogentetraoxosulphate (VI)
20
Zn (s) + CuSO 4(aq) → ZnSO 4(aq) + Cu (s)
In the reaction above, the oxidation number of the reducing agent changes from
پاسخ دهید
(B)
0 to + 2
21
\(H_2O_{(g)} + C_{(s)} → H_{2(g)} + CO_{(g)}\)
The oxidizing agent in the reaction above is
پاسخ دهید
(C)
H2O(g)
22
Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound
[Cu=64, F = 96500 Cmol-1]
پاسخ دهید
(B)
30156.3
23
How many faraday of electricity is required to produce 0.25 mole of copper?
پاسخ دهید
(D)
0.50F
24
If the change in free energy of a system is -899 Jmol-1 and the entropy change is 10Jmol-1k-1 at 250C, calculate the enthalpy change.
پاسخ دهید
(A)
+2081 Jmol-1
25
In an equilibrium reaction, which of the following conditions indicates that maximum yield of the product will be obtained?
پاسخ دهید
(A)
Equilibrium constant is very large
26
In a chemical reaction, the change in concentration of a reactant with time is
پاسخ دهید
(C)
rate of reaction
27
Fluorine does not occur in the free state in nature because
پاسخ دهید
(D)
of its high reactivity
28
In the extraction of sodium from fused sodium chloride, the anode is made of platinum because
پاسخ دهید
(D)
chlorine does not react with platinum
29
In the electrolytic extraction of calcium from calcium chloride, the cathode is
پاسخ دهید
(D)
iron
30
A compound that gives a brick-red colour to a non-luminous flame is likely to contain
پاسخ دهید
(C)
calcium ions
31
A few drops of NaOH solution was added to an unknown salt forming a white precipitate which is insoluble in excess solution. The cation likely present is
پاسخ دهید
(C)
Ca2+
32
The general formula of haloalkanes where X represents the halide is
پاسخ دهید
(D)
C nH 2n+1X
33
The alkanol obtained from the production of soap is
پاسخ دهید
(C)
glycerol
34
Ethyne is passed through a hot tube containing organo-nickel catalyst to produce
پاسخ دهید
(D)
benzene
35
Due to the unstable nature of ethyne, it is stored by dissolving in
