Post Utme University of Calabar Chemistry Past Questions and Answers

Question 16:

Separation of different carotenes from carrot root uses a method ____________

A. Centrifugation
B. Distillation
C. Chromatography
D. Carotinization

Question 17:

\begin{array}{|l|c|c|c|c|}
\hline Solution & W & \(X\) & \(Y\) & \(Z\) \\
\hline \(P h\) & 8 & 12 & 4 & 2 \\
\hline
\end{array}
From the table, which of the solutions W, C, Y and \(Z\) will liberate carbon (IV) oxide from a trioxocarbonate (IV) salt?

A. \(Z\)
B. Y
C. \(W\)
D. \(X\)

Question 18:

\(50 cm ^{3}\) of a saturated solution of \(KNO _{3}\) at \(40^{\circ} C\) contained \(5.05 g\) of the salt. What is the solubility of \(KNO _{3}\) at \(40^{\circ} C [ K =39, N =14, O =16]\)

A. \(1.0 moldm ^{-3}\)
B. \(1.5 moldm { }^{-3}\)
C. \(2.0 moldm ^{-3}\)
D. \(5.0 moldm\)

Question 19:

A brand of ink containing cobalt (III), copper (II) and iron(II) ions can best be separated into its various components by

A. Fractional crystallization
B. Fractional distillation
C. Sublimation
D. Chromatography

Question 20:

If the rate law obtained for a given reaction is given as rate \(= [K X]^{n}[ Y ]^{n}\), what is the overall order of the reaction.

A. \(n m\)
B. \(n / m\)
C. \(n+m\)
D. \(n-m\)