2022 - JAMB Chemistry Past Questions and Answers - page 2
On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell
cu\(^{2+}\)
sn\(^{2+}\)
fe\(^{2+}\)
zn\(^{2+}\)
Electrochemical series (also known as activity series of elements) is a series in which elements are arranged in an increasing or decreasing order of their standard electrode potential.
K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Ag > Au.
The addition of charcoal to the filter bed of sand during water treatment for city supply is to?
prevent goiter
prevent tooth decay
remove odour
kill germs
The addition of charcoal is to adsorb the radioactive gases within the air vacuumed from a nuclear boiling water reactor turbine condenser and retain them while they rapidly decay to non-radioactive solid species.
Using the metal activity series, the metal that can liberate hydrogen gas from steam is?
iron
copper
tin
lead
The reaction of Iron with steam forms iron oxide and hydrogen gas
An organic compound with a fishy smell is likely to have a general formula ___
RCONHR\(^1\)
A. RCONH\(_2\)
RNH\(_2\)
RCOR\(^1\)
Amines derive from ammonia (NH3) in which one or more hydrogen atoms are replaced by an alkyl or aryl group.
N\(_2\)O\(_4\) ⇔ 2NO\(_2\) (Δ = -ve)
From the reaction above, which of these conditions would produce the highest equilibrium yield for N\(_2\)O\(_4\)?
Low temperature and high pressure
Low temperature and low pressure
high temperature and low pressure
high temperature and high pressure
Low temperature and high pressure favour the highest yield for N\(_2\)O\(_4\)
Zn + 2HCL → ZnCl\(_2\) + H\(_2\)
What happens to zinc in the above reaction?
oxidized
a reactant
reduced
a metal
Zinc will be oxidized because it is a reducing agent where as HCl is an oxidizing agent.
An organic functional group which would likely decolourize ammoniacal silver nitrate is?
alkene
alkane
alkyne
alkanol
A coloured gas that is known to be poisonous and can readily damage the mucous lining of the lungs is?
hydrogen sulphide
carbon(ii)oxide
chlorine
sulphur(iv)oxide
Much exposure to chlorine gas can cause coughing, eye and nose irritation, lacrimation, and a burning sensation in the chest. This can degenerate to airway constriction, noncardiogenic pulmonary edema, hemoptysis, and bronchopneumonia.
In order to electroplate spoon with silver, the arrangement of the electrolytic cell is?
the anode is a silver rod and the cathode is the spoon
the anode is the spoon and the cathode is a silver rod
the electrolyte is silver trioxonitrate(v)( solution and the cathode is a silver rod.
the electrolyte is silver trioxonitrate(v) solution and the anode is the spoon
The steel spoon to be coated with silver is the cathode of the electrolytic cell. The anode of the electrolytic cell is made of silver metal and the electrolyte used for electroplating silver on a spoon must contain silver ions (Ag + ), for example, silver nitrate (AgNO3) or silver cyanide (AgCN) dissolved in water.
More.
An organic compound which decolorizes bromine water is likely to be?
C\(_3\)H\(_8\)
C\(_2\)H\(_6\)
C\(_4\)H\(_10\)
C\(_2\)H\(_4\)
Mixing an alkene with bromine water (or bubbling a gaseous alkene through bromine water) results in a colourless solution.