Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.
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Question 131: What is the decrease in volume of air when pyrogallol is shaken with 30.00cm3 of air ?
Options:
A) 15.00cm3
B) 6.30cm3
C) 0.63cm3
D) 0.06cm3
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The correct answer is B .
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Question 132: When pure aluminium metal is heated to red hot in the presence of nitrogen gas, the compound formed is
Options:
A) Al2N
B) Al2N2
C) AlN
D) Al2N3
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The correct answer is C .
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Question 133: When a little brine was added to a metal nitrate a white precipitate was formed which first turned violet and then black on exposure to ai. The metal nitrate is therefore?
Options:
A) sodium nitrate
B) mercuric nitrate
C) lithium nitrate
D) silver nitrate
E) potassium nitrate
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The correct answer is D .
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Question 134: The process of converting starch to ethanol is
Options:
A) cracking
B) distillation
C) fermentation
D) oxidation
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The correct answer is C .
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Question 135: When the two end alkyl groups ethyl ethanoate are interchange, the compound formed is known as
Options:
A) methyl ethanoate
B) ethyl propanaote
C) methyl propanoate
D) propyl ethanoate
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The correct answer is C .
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Question 136:
The number of electrons in the valence shell of an element of atomic number 14 is?
Options:
A) 1
B) 2
C) 3
D) 4
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The correct answer is D .
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Question 137: The solution of a sample in a tube will be identified as a chloride if it gives
Options:
A) a white precipitate on addition of AgNO3 and barium chloride solutions
B) a white precipiate when acidified with HCI, and then AgNO3 solution added
C) a white precipitate when acidified with dilute HNO3 and then AgNO3 solution added
D) a white precipitate when acidified with dilute H2SO4 and then barium nitrate solution added
E) a pungent smell of chlorine gas when dilute HCI and MnO2 are added
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The correct answer is C .
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Question 138: Given the mean atomic mass of chlorine prepared in the laboratory to be 35.5 and assuming that chlorine contains two isotopes of mass number 35 nad 37, what is the percentage composition of the isotope of mass number 35?
Options:
A) 20
B) 25
C) 50
D) 75
E) 90
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The correct answer is D .
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Question 139: Which of the following compounds will impart a brick-red colour to a non-luminious bunsen flame?
Options:
A) NaCl
B) LiCl
C) CaCl2
D) MgCl2
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The correct answer is C .
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Question 140: When hydrogen sulphide and sulphur dioxide are each passed in turn into a solution of potassium dichromate?
Options:
A) both gases change the colour of the solution from yellow to colourless
B) both gases causes sulphur to be deposited
C) only hydrogen sulphide decolourizes the solution
D) only sulphur dioxide deposits sulphur
E) only hydrogen sulphide deposits sulphur
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The correct answer is E .