Post Utme Chemistry Past Questions and Answers

Question 126:

Calculate the volume of \(\mathrm{CO}_{2}\) measured at sip produced on heating \(250 \mathrm{~g}\) of potassium hydro, trioxocarbonate(IV) strongly. \((\mathrm{K}=\) \(39, \mathrm{H}=1, \mathrm{C}=12, \mathrm{O}=16)\)

A. \(28 \mathrm{dm}^{3}\)
B. \(2.8 \mathrm{dm}^{3}\)
C. \(5.6 \mathrm{dm}^{3}\)
D. \(11.2 \mathrm{dm}^{3}\)

Question 127:

The boiling points of water, ethanol, methylbenzene and butan-2-ol are \(373.0 \mathrm{~K}, 351.3 \mathrm{~K}\), \(383.6 \mathrm{~K}\) and \(372.5 \mathrm{~K}\) respectively. Which liquid has the highest vapour pressure at \(323.0 \mathrm{~K}\)

A. Water
B. Methylbenzene
C. Ethanol
D. Butan-2-o1

Question 128:

The conclusion from Rutherford's alpha-scattering experiment is that

A. Atoms are mostly empty space with a small nucleus
B. Emissions from radioactive substances consist of three main components
C. There is a nuclear pull on orbital electron.
D. Electrons are deflected by both magnetic electric fields

Question 129:

Elements \(P, Q\) and \(R\) have atomic numbers 9,16 and 20 respectively. Which of them would gain electron(s) during ionic bonding? The change in the oxidation number of oxygen in the equation above is ____________

A. \(Q\) and \(R\)
B. \(P\) and \(R\)
C. \(P\) and \(Q\)
D. \(P, Q\) and \(R\)

Question 130:

Which of the following has the lowest pH?

A. \(5 \mathrm{~cm}^{3}\) of \(\mathrm{M} / 10 \mathrm{HCl}\)
B. \(10 \mathrm{~cm}^{3}\) of \(\mathrm{M} / 10 \mathrm{HCl}\)
C. \(20 \mathrm{~cm}^{3}\) of \(\mathrm{M} / 8 \mathrm{HCl}\)
D. \(15 \mathrm{~cm}^{3}\) of \(\mathrm{M} / 2 \mathrm{HCl}\)