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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

4,306 questions
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Question 1 of 20 4,306 total questions
Question 2001
jamb 1984
Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of
ACa(OH)2
BCaCO3
CCaHCO3
DCaSO4
EN2CO3
View Explanation & Discuss
Question 2002
jamb 1984
Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory?
AHeating ammonia gas with tetraoxosulphate (VI) acid
BHeating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid
CHeating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
DHeating potassium trioxonitrate (V) with calcium hydroxide
EHeating a mixture of ammonia gas and oxygen.
View Explanation & Discuss
Question 2003
jamb 1984
In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H2SO4 \(\to\) Na2SO4 + 2H2O is
A+ 28.65 kJ
B- 28.65KJ
C+ 57.3KJ
D- 114.6 KJ
E- 229.2 KJ
View Explanation & Discuss
Question 2004
jamb 1984
For the reaction 2Fe3+ 2I- \(\to\) 2Fe2+ + I2, which of the following statements is TRUE?
AFe is oxidized to Fe3+
BFe3+ is oxidized to Fe2+
CI- is oxidized to I2
DI- is reduced to I2
EI- is displacing an electron from Fe3+
View Explanation & Discuss
Question 2005
jamb 1984
In which of the following reactions does hydrogen peroxide act as a reducing agent?
AH2S + H2O2 \(\to\) S + 2H2O
BPbSO3 + H2O2 \(\to\) PbSO4 + H2O
C2I+ 2H+ + H2O2 \(\to\) I2 + 2H2O
DPbO2 + 2HNO3 + H2O2 \(\to\) Pb(NO3)2 + 2H2O + O2
ESO2 + H2O2 \(\to\) H2SO4
View Explanation & Discuss
Question 2006
jamb 1984
Which of the following mixtures would result in a solution of pH greater than 7?
A25.00 cm3 of 0.05 M H2SO4 and 25.00cm3 of 0.50 M Na2CO3
B25.00 cm3 of 0.05 M H2SO4 and 25.00 cm3 of 0.10 M NaHCO3
C25.00 cm3 of 0.11 MH2SO4 and 25.00cm3 0. 10 M NaOH
D25.00cm3 of 0.11 MH2 SO4 and 50.00 cm3 of 0.05 M NaOH
E25.00cm3 of 0.25 M H2SO4 and 50.00cm3 of 0.20 M NaOH
View Explanation & Discuss
Question 2007
jamb 1984
The balanced equation for the reaction of tetraoxosulphate(VI)acid with aluminium hydroxide to give water and aluminium tetraoxosulphate(VI) is
AH2SO4 + Al(OH)2 \(\to\) 2H2O + AlSO4
B3H2SO4 + 2Al(OH)3 \(\to\) 6H2O + Al2(SO4)3
C3H2SO4 + 2AlH \(\to\) 6H2O + Al(SO4)3
D3H2 SO4 + 2Al(OH)3 \(\to\) Al(SO4)3
EH2SO4 + Al(OH)3 \(\to\) H2O + Al2(SO4)3
View Explanation & Discuss
Question 2008
jamb 1984
The ratio of the number of molecules in 2g of hydrogen to that in 16g of oxygen is
A2:1
B1:1
C1:2
D1:4
E1:8
View Explanation & Discuss
Question 2009
jamb 1984
Naphthalene when heated melts at 354 K (81 oC). At this temperature the molecules of naphthalene
Adecompose into smaller molecules
Bchange their shape
Care oxidized by atmospheric oxygen
Dcontract
Ebecome mobile as the inter molecular forces are broken
View Explanation & Discuss
Question 2010
jamb 1984
Which among the elements 1. Carbon 2. Oxygen 3. Copper 4. Bromine 5. Zinc, will NOT react with either water or steam?
A1 and 2
B2 and 3
C3 and 4
D1, 2, and 3
E2, 3, and 5
View Explanation & Discuss
Question 2011
jamb 1984

A molar solution of caustic soda is prepared by dissolving

A40 g NaOH in 100 g of water
B40 g NaOH in 1000 g of water
C20 g NaOH in 500 of solution
D20 g NaOH in 1000 g of solution
E2o g NaOH in 80 g of solution
View Explanation & Discuss
Question 2012
jamb 1984

For the reaction NH4NO2 \(\to\) N2 + 2H2O, calculate the volume of nitrogen that would be produced at S. T. P from 3.2 g of the dioxonitrate(iii)salt. (Relative atomic masses: N = 14, O = 16, H = 1)

A2.24 dm 3
B2.24 cm3
C1. 123
D1. 12dm 3
E4. 48 dm 3
View Explanation & Discuss
Question 2013
jamb 1984

20 cm\(^3\) of hydrogen gas are sparked with 20cm\(^3\) of oxygen gas in an endimoeter at 373k (100\(^0\)C) and 1 atmosphere. The resulting mixture is cooled to 298 K (25 oC) and passed over calcium chloride. The volume of the residual gas is

A40 cm 3
B20 cm 3
C30 cm 3
D10cm 3
E5cm 3
View Explanation & Discuss
Question 2014
jamb 1984
Sodium chloride may be obtained from brine by
Atitration
Bdecantation
Cdistillation
Devaporation
Esublimation
View Explanation & Discuss
Question 2015
jamb 1983

In the experiment above, a current was passed for 10 minutes, and 0.63g of copper was found to be deposited on the cathode of CuSO4 cells. The weight of silver deposited on the cathode of AgNO3 cell during the same period would be? [Cu = 63, Ag = 108]

A0.54g
B1.08g
C1.62g
D2.16g
E3.24g
View Explanation & Discuss
Question 2016
jamb 1983

In the above experiment, the litmus paper will initially

Abe bleached
Bturn green
Cturn red
Dturn blue
Eturn black
View Explanation & Discuss
Question 2017
jamb 1983
30 cm3 of 0.1 M Al (NO3)3 SOLUTION IS RECTED WITH 100cm3 of 0.15M of NaOH solution. Which reactant is in excess, and by now much ?
ANaOH solution by 70 cm3
BNaOH solution, by 60 cm3
CNaOH solution by 40 cm3
DAl(NO3)3 solution by 20 cm3
EAl(NO3)3 solution by 10 cm3
View Explanation & Discuss
Question 2018
jamb 1983

\(Zn + H_2 SO_4 → ZnSO_4 + H_2\)

in the above reaction, how much zinc will be left undissolved if 2.00g of zinc is treated with 10cm^3 of 1.0 M of \(H_2SO_4\)?
[Zn =65, s = 32, O = 16, H = 1]

A1.35g
B1.00g
C0.70g
D0.65g
E0.00g
View Explanation & Discuss
Question 2019
jamb 1983
zn + 2HCl → ZnCl2 + H2

The rate of the above reaction will be greatly increased if
Athe zinc is in the powered form
Ba greater volume of the acid is used
Ca smaller volume of the acid is used
Dthe reaction vessel is immersed in an ice-bath
Ethe zinc is in the form of pellets
View Explanation & Discuss
Question 2020
jamb 1983
The equilibrium reaction between copper (l) chloride and chlorine at 25oC and 1 atmosphere is represented by the equation:
2CuCl +Cl2 ⇌ 2 CuCl2 ∆H = - 166 KJ. Which of the following statements is TRUE for the reaction, pressure remaining constant?
Amore CuCl is formed at 40oC
Bmore CuCl2 is formed at 10oC
CLess CuCl2 is formed at 10oC
Dthere is no change in the amount of CuCl2 formed at 40oC and10oC
Emore CuCl is consumed at 40oC
View Explanation & Discuss
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