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Saturday, 13 June 2026
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Chemistry Past Questions and Answers

Jamb 1983 Chemistry Questions

Question 11:
An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.
Reaction of X with yeast forms the basis of the
  • A Plastic industry
  • B Textile industry
  • C Brewing industry
  • D Soap industry
  • E Dyeing industry
View Answer & Explanation
Question 12:
A mixture of common salt, ammonium chloride and barium sulphate can best be separated by
  • A Addition of water followed by filtration then sublimation
  • B Addition of water followed by sublimation then filtration
  • C Sublimation followed by addition of water then filtration
  • D Fractional distillation
  • E Fractional crystallization
View Answer & Explanation
Question 13:
Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour?
  • A P \(\alpha\) VT
  • B P \(\alpha\) T/V
  • C PT \(\alpha\) V
  • D PV \(\alpha\) I/T
  • E P \(\alpha\) V/T
View Answer & Explanation
Question 14:
The colour imparted to a flame by calcuium ion is
  • A Green
  • B Blue
  • C Brick-red
  • D Yellow
  • E Lilac
View Answer & Explanation
Question 15:
In the reaction M + N P;∆H = + QKJ. Which of the following would increase the concentration of the product?
  • A Decreaseing the concentration of N
  • B Increasing the concentration of P
  • C Adding a suitable catalyst
  • D Decreasing the temperature
  • E Increasing the temperature
View Answer & Explanation