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Chemistry Past Questions

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Substances employed as drying agents are usually
  • A. Hygroscopic
  • B. Efflorescent
  • C. Acidic
  • D. Amphoteric
The sulphide which is insoluble in dilute hydrochloric acid is
  • A. CuS
  • B. Na2S
  • C. FeS
  • D. ZnS
The decolourization of the purple colour of a tetraoxomanganate (VII) ion is a test for
  • A. Alkanals
  • B. Alkanes
  • C. Alkenes
  • D. Alkanols
6AgNO3(aq) + PH3(g) + 3H2O(l) → 6Ag(s)+ H3PO3(aq) + 6HNO3(aq) In the reaction above, the reducing agent is
  • A. H2O(l)
  • B. PH3(g)
  • C. AgNO3(aq)
  • D. HNO3(AQ)
Group IA metals are not found free in nature because they
  • A. Have high melting and boiling points
  • B. Conduct heat and electricity
  • C. Are very reactive and unstable
  • D. Are malleable and ductile
Which of the following is found in cotton
  • A. Starch
  • B. Cellulose
  • C. fat
  • D. oil
The most important use of hydrogen is in the
  • A. Hydrogenation of oils
  • B. Manufacture of methyl alcohol
  • C. Manufacture of ammonia
  • D. Manufacture of ethyl alcohol
NH3(g) + HCI(g) → NH4CI(s) The entropy change in the system is
  • A. Negative
  • B. Indeterminate
  • C. Positive
  • D. Zero
Environmental pollution is worsened by the release from automobile exhausts of
  • A. Water vapour
  • B. Steam
  • C. Smoke
  • D. Heavy metals
When 5.0cm3 of a saturated solution of sugar of molar mass 342g at 400C was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 400C is
  • A. 7.0 mol dm-3
  • B. 3.5 mol dm-3
  • C. 2.0 mol dm-3
  • D. 10.0mol dm-3