Post Utme Chemistry Past Questions and Answers

Question 931:

How many faradays of electricity are required to deposit \(0.20\) mole of nickel if \(0.10\) taraday electricity deposited \(2.9 .8 g\) of nickel during electrolysis its aqueous solution? \(( N =58\) if \(96500 m^{-1}\) )

A. \(0.20\)
B. \(0.39
C. 0.40
D. 0.50\)

Question 932:

In the process of silver plating a metal M the metal \(M\) is the _____________

A. Anode and a direct current is used
B. Cathode and an alternating cuncent' is used
C. Anode and an alternating current is used
D. Cathode and direct current is used.

Question 933:

When a gas is compressed at very low temperature _____________

A. Its density decreases
B. It liquefies
C. Its temperatere decreases
D. Temperature increases

Question 934:

The enthalpy changes for the atomization of methane and ethane are 1648 and \(2820 kJmol ^{-1}\) respectively. The \(C - C\) mean bond dissociation energy in \(kJmol ^{-1}\) is therefore ____________

A. 348
B. \(-348\)
C. 1176
D. \(-1176\)

Question 935:

What volume of \(0.750 moldm ^{-3} Na _{2} CO _{3}\) solution could be diluted to \(250 cm ^{3}\) to reduce the concentration to \(0.025 moldm ^{-3}\) ?

A. \(16.0 cm ^{3}\)
B. \(14.2 cm ^{3}\)
C. \(10.4 cm ^{3}\)
D. \(8.3 cm 3\)