Welcome to Schoolngr.com

Search SchoolNGR

Sunday, 09 August 2026
Register . Login

Chemistry Past Questions and Answers

Chemistry Questions

Question 416:
JAMB 1985
Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably?
SchoolNGR Classroom
  • A Na<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • B Na<sub style='font-size: smaller;'>2</sub>S
  • C Na<sub style='font-size: smaller;'>2</sub>S<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>3</sub>.5H<sub style='font-size: smaller;'>2</sub>O
  • D Na<sub style='font-size: smaller;'>2</sub>CO<sub style='font-size: smaller;'>3</sub>
  • E NaHCO<sub style='font-size: smaller;'>3</sub>
View Answer & Explanation
Question 417:
JAMB 1985
The process involved in the conversion of an oil into margarine is known as?
SchoolNGR Classroom
  • A Hydrogenation
  • B Condensation
  • C Pyrolysis
  • D Dehydration
  • E Cracking
View Answer & Explanation
Question 418:
JAMB 1985
An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH<sub style='font-size: smaller;'>3</sub> (iii) with dilute HCl. The cation present in the inorganic salt is?
SchoolNGR Classroom
  • A Na<sub style='font-size: smaller;'>4</sub><sup style='font-size: smaller;'>+</sup>
  • B Ca<sup style='font-size: smaller;'>++</sup>
  • C Zn<sup style='font-size: smaller;'>++</sup>
  • D Al<sup style='font-size: smaller;'>+++</sup>
  • E Pb<sub style='font-size: smaller;'>++</sub>
View Answer & Explanation
Question 419:
JAMB 1985
Which of the following roles does sodium chloride play in soap preparation? It
SchoolNGR Classroom
  • A Reacts with glycerol
  • B Purifies the soap
  • C Accelerates the decomposition of the fat or oil
  • D Separates the soap from the glycerol
  • E Converts the fatty acid to its sodium salt
View Answer & Explanation
Question 420:
JAMB 1985
The function of sulphur during vulcanization rubber is to?
SchoolNGR Classroom
  • A Act as catalyst for the polymerization of rubber molecules
  • B Convert rubber from thermosetting to thermo plastics polymer
  • C From chains which bind rubber molecules together
  • D Break down rubber polyer
  • E Shorten the chain length of rubber polyer
View Answer & Explanation

Stay Updated

Follow us on:


Subjects