Question

The results of five experiments are shown below:

Mg(s) + Co ²⁺ --> Mg ²⁺ + Co(s)
Co(s) + Ni ²⁺ --> Co ²⁺ + Ni(s)
Ni(s) + Hg ²⁺ --> Hg(l) + Ni ²⁺
Co(s) + 2 Ag ⁺ --> 2 Ag(s) + Co ²⁺
Hg(l) + 2 Ag ⁺ --> 2 Ag(s) + Hg ²⁺

On the basis of these data, the best competitor for electrons (easiest to reduce) is:

	a.	Ag+
	b.	Hg2+
	c.	Co2+
	d.	Ni2+
	e.	Mg2+

According to Le Chatelier's principle, which of the following would NOT increase the voltage of the cell below?

Ag+ + e --> Ag(s)	E° = +0.80 volt
Cu2+ + 2e --> Cu(s)	E° = +0.34 volt

	a.	increasing the concentration of Ag+(aq)
	b.	increasing the concentration of 1 mol/L Cu2+(aq) in the Cu2+-Cu half-cell.
	c.	adding AgNO3(s) to the Ag+-Ag half-cell.
	d.	precipitating copper ion as CuS by the addition of Na2S solution.

A cell is made by connecting and Ag ⁺-Ag half-cell with a Sn ²⁺-Sn half-cell. Which of the following equations represents the overall reaction of the cell?

	a.	2 Ag+ + Sn --> 2 Ag + Sn2+
	b.	Sn2+ + Ag --> Sn + Ag+
	c.	Ag+ + 2 Sn --> Ag + 2 Sn2+
	d.	Sn2++2 Ag -> Sn + 2 Ag+

Answer 1

1) The best competitor of electrons is Ag+.

Answer is a).

2) Answer is b) increasing concentration of 1mol/L Cu2+ in Cu2+Cu half cell will not increase the voltage of cell.

3) Answer is a). Since Sn has high reduction potential thus it will gain electron and Ag will lose electron.