Question

Given : $E_{A{g}^{\oplus }|Ag}^{\ominus }=0.80V,E_{M{g}^{2+}|Mg}^{\ominus }=-2.37V$; $E_{C{u}^{2+}|Cu}^{\ominus }=0.34V.E_{H{g}^{2+}|Hg}^{\ominus }=0.79V$

Which of the following statements is/ are incorrect ?

• A. $AgN{O}_3$ can be stored in copper vessel.
• B. $Cu(N{O}_3{)}_2$ can be stored in magnesium vessel.
• C. $CuC{l}_2$ can be stored in silver vessel.
• D. $HgC{l}_2$ can be stored in copper vessel.

Answer 1

Answer: (A), (B), (D)

The correct options are
A $AgN{O}_3$ can be stored in copper vessel.
B $Cu(N{O}_3{)}_2$ can be stored in magnesium vessel.
D $HgC{l}_2$ can be stored in copper vessel.

If $E_{cell}^{\ominus }>0$, then the reaction is spontaneous.

a. $E_{cell}^{\oplus }=0.8-0.34=0.46V$ $(2A{g}^{\oplus }+Cu\to 2Ag+C{u}^{2+})$

b. $E_{cell}^{\ominus }=0.34-(-2.37)=2.81,V$

$(C{u}^{2+}+Mg\to Cu+Cu+M{g}^{2+})$

c. $E_{cell}^{\ominus }=0.34-0.8=-0.46V$

$(C{u}^{2+}+2Ag\to Cu+2A{g}^{2+})$

d. $E_{cell}^{\ominus }=0.79-0.34=0.45V$

$(H{g}^{2+}+Cu\to C{u}^{2+}+Hg)$

In (a), (b), and (d), $E_{cell}^{\ominus }>0$ which means that the respective solution in the respective vessel cannot be stored.

Hence correct options are A, B and D.