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Friday, 19 June 2026
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Chemistry Past Questions and Answers

Topic: Separation of mixtures and purification of chemical substances

Jamb Chemistry Questions - Separation of mixtures and purification of chemical substances

Question 306:
How many atoms are present in 6.0g of magnesium?
[Mg = 24, NA = 6.02 x 1023 mol-1]
  • A 1.20 x 10<sup style='font-size: smaller;'>22</sup>
  • B 2.41 x 10<sup style='font-size: smaller;'>22</sup>
  • C 1.51 x 10<sup style='font-size: smaller;'>23</sup>
  • D 3.02 x 10<sup style='font-size: smaller;'>23</sup>
View Answer & Explanation
Question 307:
I. It has a varied composition from one place to another. ll. it constituents can be separated by physical means
lll. It contains unreactive noble gases
which of the above shows that air is a mixture?
  • A I and ll only
  • B Ll and lll only
  • C L and lll only
  • D L,lll and lll
View Answer & Explanation
Question 308:
Potassium trioxochlorate (V)has a solubility of 1.5 mol dm -3 at 45 oC.On cooling this solution to a temperature of 20 oC, the solubility was found to be 0.5 mol dm -3. What mass of KCIO 3 was crystalized out?
[K = 39, Cl = 35.5 O =16]
  • A 1.00g
  • B 10.00g
  • C 12.25g
  • D 122.50g
View Answer & Explanation
Question 309:
Which of the following will produce a solution with pH less than 7 at equivalent point?
  • A HNO <sub style='font-size: smaller;'>3</sub> +NaOH
  • B H <sub style='font-size: smaller;'>2</sub>SO <sub style='font-size: smaller;'>4</sub> + KOH
  • C HC +Mg (OH) <sub style='font-size: smaller;'>2</sub>
  • D HNO <sub style='font-size: smaller;'>3</sub> + KOH
View Answer & Explanation
Question 310:
The number of hydroxonium ions produced by one molecule of an acid in aqueous solution is its
  • A Basicity
  • B Acid strength
  • C PH
  • D Concentration
View Answer & Explanation