4. What current is drawn by a 90 W light bulb on a 110 V household circuit?
1 answer:
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Answer:
E°cell = - 1.3575 V
This reaction is spontaneous in the reverse direction
Explanation:
The given cell reaction:
Cr³⁺(1.32 × 10⁻³ M) + Fe²⁺(aq) → Cr²⁺(aq) + Fe³⁺(1.14 M)
The given Gibbs free energy: ΔG = 131 kJ = 131 × 10³ J (∵ 1 kJ = 10³ J)
As we know,
ΔG = - n F E°cell
Here, n - the number of moles of electrons transferred = 1
F - Faraday constant = 96500
E°cell - cell potential = ?
<u>For a given chemical reaction if-</u>
1. ΔG = negative and E°cell = positive
⇒ <em>The reaction is spontaneous and proceeds spontaneously in the forward direction.</em>
2. ΔG = positive and E°cell = negative
⇒ <em>The reaction is non-spontaneous and proceeds spontaneously in the reverse direction.</em>
<u>Since, for this chemical reaction: </u>
Cr³⁺(1.32 × 10⁻³ M) + Fe²⁺(aq) → Cr²⁺(aq) + Fe³⁺(1.14 M)
ΔG = + 131 × 10³ J ⇒ positive
and, E°cell = - 1.3575 V ⇒ negative
<u>Therefore, this reaction is spontaneous in the reverse direction.</u>