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Chemistry Past Questions and Answers

Jamb Chemistry Questions

Question 26:

How will a metal X, which reacts explosively with air and with dilute acids be best extracted from its ores?

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A Electrolysis of solution of its salts
B Decomposition of its oxides
C Displacement from solution by an alkali metal
D Electroiysis of fused salt

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Question 27:

Which of the following is NOT correct test for the named organic compound in each case?

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A Butanoic acid solution gives effervescence with Na₂CO₃ solution
B Glucose when reacted with Na₂CrO₄ at 0°C will show immediate discharge of colour
C When but-2-ene is reacted with dilute solution of KMnO₄ the purple colour of KMnO is discharged readily even room temperature
D When butan-2-ol is boiled with butanoic acid with a drop of concentrated H₂SO₄ a sweet smelling liquid is produced

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Question 28:

Which of the following is used as an 'anti-knock' in automobile engines?

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A Tetramethyl silane
B Lead tetra-ethyl
C Glycerol
D N-heptane

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Question 29:

What reaction takes place when palm-oil is added to potash and foam are observed?

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A Neutralization
B Saponification
C Esterification
D Salting-out

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Question 30:

When ethanol is heated with excess concentrated sulphuric acid, the ethanol is?

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A Oxidized to ethene
B Polymerized to polyethene
C Dehydrated to ethene
D Dehydrated to ethyne

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