If E Ni 2+ mid Ni °=0.25 V , E Cu 2+ mid Cu °=0.34 V , E Ag + mid Ag °=0.8 V and EZ n2+ mid Z n0=-0.76 V , then which of the following reactions under standard condition will not take place in the specified direction spontaneously ?

Question

If E Ni 2+ mid Ni °=0.25 V , E Cu 2+ mid Cu °=0.34 V , E Ag + mid Ag °=0.8 V and EZ n2+ mid Z n0=-0.76 V , then which of the following reactions under standard condition will not take place in the specified direction spontaneously ? (A) Cu ( s )+ Ni ( aq. )2+ arrow Cu ( aq .)2++ Ni (s) (B) Cu ( s )+2 Ag ( aq. )+ arrow Cu ( aq .)2++2 Ag ( s ) (C) Cu ( s )+ Zn ( aq .)+2 arrow Cu ( aq .)2++ Zn ( s ) (D) Both (a) (c)

Tardigrade Admin · Accepted Answer

Since, Cu +2 / Cu has higher standard reduction potential than Ni +2 / Ni Zn +2 / Zn ∴ Cu +2 gets reduced faster than Ni +2 Zn +2

Q. If $E_{N i^{2 +} ∣ N i}^{\circ} = 0.25 V, E_{C u^{2 +} ∣ C u}^{\circ} = 0.34 V, E_{A g^{+} ∣ A g}^{\circ} = 0.8 V$ and $E_{Z n^{2 +} ∣ Z n}^{0} = - 0.76 V,$ then which of the following reactions under standard condition will not take place in the specified direction spontaneously ?

$C u_{(s)} + N i_{(a q .)}^{2 +} \to C u_{(a q .)}^{2 +} + N i_{(s)}$

$C u_{(s)} + 2 A g_{(a q .)}^{+} \to C u_{(a q .)}^{2 +} + 2 A g_{(s)}$

$C u_{(s)} + Z n_{(a q .)}^{+ 2} \to C u_{(a q .)}^{2 +} + Z n_{(s)}$

Both (a) & (c)

Since, $C u^{+ 2} / C u$ has higher standard reduction potential than $N i^{+ 2} / N i & Z n^{+ 2} / Z n$

$∴ C u^{+ 2}$ gets reduced faster than $N i^{+ 2} & Z n^{+ 2}$

Q. If ENi2+∣Ni∘​=0.25V,ECu2+∣Cu∘​=0.34V,EAg+∣Ag∘​=0.8V and EZn2+∣Zn0​=−0.76V, then which of the following reactions under standard condition will not take place in the specified direction spontaneously ?

Cu(s)​+Ni(aq.)2+​→Cu(aq.)2+​+Ni(s)​

Cu(s)​+2Ag(aq.)+​→Cu(aq.)2+​+2Ag(s)​

Cu(s)​+Zn(aq.)+2​→Cu(aq.)2+​+Zn(s)​