The reaction between sulphur (IV) oxide and oxygen is represented by the equilibrium reaction 2SO2(g) + O2(g) ↔ 2SO3(g), ∆H = -196 kJ. What factor would influence increased production of SO3(g)?
คำตอบ
(C)
Decrease in the temperature of the reaction
2
Magnesium ribbon was allowed to burn inside a given gas P leaving a white solid residue Q. Addition of water to Q liberated a gas which produced dense white fumes with a drop of hydrochloric acid. The gas P was?
คำตอบ
(A)
nitrogen
3
The best treatment for a student who accidentally poured concentrated tetraoxosulphate (VI) acid on his skin in the laboratory is to wash the skin with?
คำตอบ
(A)
cold water
4
In which of the following pairs of element is allotropy exhibited by each element?
คำตอบ
(D)
Oxygen and sulphur
5
Which of the following gases can best be used for demonstrating the fountain experiment?
i) Nitrogen (ii) Ammonia (iii) Nitrogen (I) oxide
(iv) Hydrogen chloride.
คำตอบ
(C)
ii and iv
6
When sodium hydroxide is heated with ammonium tetraoxosulphate (IV), the gas given off may be collected by?
คำตอบ
(C)
passing it directly through calcium oxide
7
Which of the following elements will form oxide which will dissolve both in dilute HNO3 and NaOH solutions to form salts?
คำตอบ
(A)
Al
8
Stainless steel is an alloy of?
คำตอบ
(C)
iron, carbon and chromium
9
Alloys are best prepared by?
คำตอบ
(D)
cooling a molten mixture of the necessary elements
10
Corrosion is exhibited by?
คำตอบ
(D)
all metals
11
Inspite of the electronic configuration, 1s22s22p2, carbon is tetraavalent because?
คำตอบ
(C)
both the 2s and 2p orbitals hybridizes
12
Which of the following compounds will give a precipitate with an aqueous ammoniacal solution of copper (l) chloride?
คำตอบ
(B)
CH3 ≡ CCH3
13
The efficiency of petrol as a fuel in high-compression internal combustion engines improves with an increase in the amount of?
คำตอบ
(A)
branched chain alkanes
14
Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is?
คำตอบ
(B)
triodomethane
15
The most volatile fraction obtained from fractional distillation of crude petroleum contains?
คำตอบ
(D)
methane, ethane and propane
16
Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the?
คำตอบ
(C)
alkali
17
Synthetic rubber is made by polymerization of?
คำตอบ
(A)
2 methyl buta - 1, 3 - diene
18
Complete oxidation of propan -1- ol gives?
คำตอบ
(D)
propanoic acid
19
When water drops are added to calcium carbide in a container and the gas is passed through a jet and lifted, the resultant flame is called an?
คำตอบ
(C)
oxyacetylene flame
20
The greater the different in electronegativity between bonded atoms, the?
คำตอบ
(B)
higher the polarity of the bond
21
A stream of air was successively passed through three tubes X, Y and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of the gas emanating from tube Z?
คำตอบ
(D)
water vapour, N2 and the inert gases
22
In the purification of town water supply, alum is used principally to?
คำตอบ
(D)
coagulate small pasrticles of mud
23
Which of the following water samples will have the highest titre value when titrated for the Ca2+ ions using soap solution?
คำตอบ
(A)
Permanently hard water after boiling
24
Oil spillage in ponds and creeks can be cleaned up by?
คำตอบ
(B)
spraying with detergent
25
The solubility of Na3AsO4(H2O)12 is 38.9g per 100g H2O. What is the mass percentage of Na3AsO4 in the saturated solution?
(As = 75, Na = 23, O = 16, H = 1)
คำตอบ
(D)
13.7%
26
In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity?
คำตอบ
(C)
Hydrochloride acid, ethanol acid, sodium chloride, milk of magnesia and sodium hydroxide
27
If 24.83 cm3 of 0.15 M NaOH is titrated to its end point with 39.45 cm3
of HCl, what is the molarity of the HCl?
คำตอบ
(A)
0.094 M
28
The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is?
คำตอบ
(C)
Metallic
29
If d represents the density of a gas and K is a constant, the rate of gaseous diffusion r is related to d by the equation?
คำตอบ
(A)
r = k/√d
30
An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope?
