2015 - JAMB Chemistry Past Questions and Answers - page 2
11
Which of the noble gases has the greatest ionization energy
A
He
B
Xe
C
Ar
D
Rr
correct option: a
Helium has the greatest ionization energy because they are less stable. Options B,C,D have low ionization energy because one more stable and do not react easily
Users' Answers & Comments12
The weakest attractive force that can be observed between two molecules is
A
ionic
B
covalent
C
co-ordinate covalent
D
vander Waals
correct option: d
Vander Waals are the weakest attractive forces that exist between two molecules. Option A,B,C are not weak forces because the force attraction that exist between their interested molecule are very strong
Users' Answers & Comments13
An elements used in production of matches is
A
nitrogen
B
aluminum
C
copper
D
sulphur
correct option: d
Sulphur is an element that burns with a strongly explosive smell, as a result it is explosive smell
Users' Answers & Comments14
Cathode rays cause an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays
A
are positively charged
B
are negatively charged
C
Have mass
D
travel in straight lines
correct option: d
Rays travels in straight lines and finds its way through any opening available. It could be refracted, reflected or transmitted based on any obstacle. Option A,B,C are not the reason why the cathode are coasted shadows
Users' Answers & Comments15
Flow of current in electrolytes is due to the movement of
A
electrons
B
Holes and electron
C
Ions
D
Charges
correct option: c
Users' Answers & Comments16
A suitable reagent for distinguish between ethanoic and ethanol is
A
bromine water
B
Fehling’s solution
C
sodium hydrogen trioxocarbonate (iv)
D
Ammoniacal silver trioxonitrate(V)
correct option: c
Sodium hydrogen trionocarbonate iv is the only distinguishing reagent between ethanoic and ethanol. Option A, B, D are not conspicuous in distinguishing between ethanoic and ethanol
Users' Answers & Comments17
In the discovery of protein, the instrument used is
A
cathode ray tube
B
glass tube and discharge tube
C
discharge tube with terminal cathode
D
discharge tube with central cathode
correct option: d
Discharge tube with central cathode is an apparatus for producing cathode rays and positive rays. Option A,B,C will not yield cathode rays and positive rays
Users' Answers & Comments18
A
chlorine
B
nitrogen
C
calcium
D
neon
correct option: b
Nitrogen has an electronic configuration of 7 i.e
1s2 2ps2 2p3. option A,C,D are chlorine 17, calcium 20, neon 10
Users' Answers & Comments1s2 2ps2 2p3. option A,C,D are chlorine 17, calcium 20, neon 10
19
Which of the following metals burns with brick red
A
Pb
B
Ca
C
Na
D
Mg
correct option: b
Calcium is the only metal that burn with brick red flame. Option A,C,D will not burn with brick red flame rather burn with brick blue flame
Users' Answers & Comments20
In the production of soap, concentrated sodium chloride solution is added to
A
increase the solubility of soap
B
decrease the solubility of the soap
C
saponify the soap
D
emulsify the soap
correct option: b
Concentrated sodium chloride solution will the solubility of soap along the course of soap production. Options A,C,D are not appropriate
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