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NEET CHEMISTRYElectrochemistryMedium

Question

The EMF of a Daniel cell at 298 K298\text{ K} is E1E_1: ZnZnSO4(0.01 M)CuSO4(1.0 M)CuZn|ZnSO_4(0.01\text{ M}) || CuSO_4(1.0\text{ M})|Cu. When the concentration of ZnSO4ZnSO_4 is 1.0 M1.0\text{ M} and that of CuSO4CuSO_4 is 0.01 M0.01\text{ M}, the EMF is changed to E2E_2. The correct relationship between E1E_1 and E2E_2 is:

A

E1>E2E_1 > E_2

B

E1<E2E_1 < E_2

C

E1=E2E_1 = E_2

D

E2=0E1E_2 = 0 \neq E_1

Step-by-Step Solution

The cell reaction for a Daniell cell is: Zn(s)+Cu2+(aq)Zn2+(aq)+Cu(s)Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s)

According to the Nernst equation at 298 K298\text{ K}: Ecell=Ecell0.05912log[Zn2+][Cu2+]E_{cell} = E^{\circ}_{cell} - \frac{0.0591}{2} \log \frac{[Zn^{2+}]}{[Cu^{2+}]}

For the first case (E1E_1): [Zn2+]=0.01 M=102 M[Zn^{2+}] = 0.01\text{ M} = 10^{-2}\text{ M} and [Cu2+]=1.0 M[Cu^{2+}] = 1.0\text{ M} E1=Ecell0.05912log(1021)=Ecell0.05912(2)=Ecell+0.0591 VE_1 = E^{\circ}_{cell} - \frac{0.0591}{2} \log \left(\frac{10^{-2}}{1}\right) = E^{\circ}_{cell} - \frac{0.0591}{2} (-2) = E^{\circ}_{cell} + 0.0591\text{ V}

For the second case (E2E_2): [Zn2+]=1.0 M[Zn^{2+}] = 1.0\text{ M} and [Cu2+]=0.01 M=102 M[Cu^{2+}] = 0.01\text{ M} = 10^{-2}\text{ M} E2=Ecell0.05912log(1102)=Ecell0.05912(2)=Ecell0.0591 VE_2 = E^{\circ}_{cell} - \frac{0.0591}{2} \log \left(\frac{1}{10^{-2}}\right) = E^{\circ}_{cell} - \frac{0.0591}{2} (2) = E^{\circ}_{cell} - 0.0591\text{ V}

Comparing E1E_1 and E2E_2, we get E1>E2E_1 > E_2.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Electrochemistry. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYElectrochemistrydanielznznsotextcusotextconcentrationchanged

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