Post Utme Obafemi Awolowo University Chemistry Past Questions and Answers

Question 11:

During electrolysis, two cells each containing molten \(Al _{2} O _{3}\) and fuse \(CaCl _{2}\) were connected in series. A current of \(15 Amp\) was passed through the cells for a given period of time. At the end of the electrolysis \(9 g\) of calcium was found to have been deposited at the cathode. What mass of aluminum would be deposited in the second cell. [A = \(27, Ca =40]\)

A. \(8.82 g\)
B. \(4.44 g\)
C. \(17.60 g\)
D. \(4.05 g\)

Question 12:

The balanced equation for the reaction of tin(II) salt with potassium heptaoxodichloromate (VI) in an acidic medium can be represented as \(SSn ^{2+}+ fCr _{2} 2 O _{7}^{2-}+ gH ^{+} \rightarrow hSn ^{4+}+ i -\) \(Cr ^{3+}+ jH _{2} O .\) e, \(f , g , i\) and \(j\) respectively

A. \(3,5,6,1\) and \(4\)
B. \(3,1,14,3,2\) and 7
C. \(3,2,6,1,5\) and 6
D. \(5,2,1,5,3\) and 2

Question 13:

The \(pH\) of a solution containing \(0.5 \times 10^{-6} M H _{2} SO _{4}\) is ____________

A. \(6.3\)
B. \(6.5\)
C. \(6.0\)
D. \(5.0\)

Question 14:

Which of the following oxides will NOT dissolve in both dilute hydrochloric acid and \(2 M\) sodium hydroxide solution?

A. Lead (II) oxide
B. Aluminum oxide
C. Zinc (II) oxide
D. Calcium oxide

Question 15:

The I.U.P . A . C . name for the compound [image] is ____________

A. Pent \(-3\) - enoic acid
B. Pent \(-4\) - enoic acid
C. Pent 2 - enoic acid
D. Pent \(-3\) - ene \(-1-\) oic acid