Post Utme Chemistry Past Questions and Answers

Question 266:

The colour of methyl orange in alkaline medium is ____________

A. Orange
B. Red
C. Yellow
D. Pink

Question 267:

A compound contains \(40.0 \%\) carbon, \(6.7 \%\) hydrogen and \(53.3 \%\) oxygen. If the molar mass of the compound is 180 , find the molecular formula.

A. \(\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{3}\)
B. \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)
C. \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{3}\)
D. \(\mathrm{CH}_{2} \mathrm{O}\)

Question 268:

Which of these represents redox reaction?

A. \(\mathrm{AgNO}_{3}+\mathrm{NaCl} \rightarrow \mathrm{AgCl}+\mathrm{NaNO}_{2}\)
B. \(\mathrm{H}_{2} \mathrm{~S}+\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2} \cdots \mathrm{PbS}+2 \mathrm{HNO}_{3}\)
C. \(\mathrm{CaCO}_{3} \rightarrow \mathrm{CaO}+\mathrm{CO}_{2}\)
D. \(\mathrm{Zn}+2 \mathrm{HCl} \rightarrow \mathrm{ZnCl}_{2}+\mathrm{H}_{2}\)

Question 269:

The acid that is used to remove rust is ____________

A. Boric
B. Trioxonitrate (V)
C. Hydrochloric
D. Tetraoxosulpate (VI)

Question 270:

A compound commonly used for the sterilization and preservation of specimens and food is ____________

A. Ethanol
B. Benzene
C. Ether
D. Ammonia