The mass of silver (Molar mass of ) displaced by a quantity of electricity which displaces 5600 mL of at S.T.P. will be ______ g.
Answer: 108
Solution
According to Faraday's laws of electrolysis, the same quantity of electricity will displace equivalent amounts of different substances.
Equivalents of Ag = Equivalents of O₂
Let x g of silver be displaced.
For Silver:
For Oxygen:
Applying equivalence:
Answer: 108
Note: If using molar volume = 22.7 L (newer STP definition), the answer would be 107 g, which is also accepted.
Equivalents of Ag = Equivalents of O₂
Let x g of silver be displaced.
For Silver:
- Equivalent weight of Ag = Molar mass / n-factor = 108/1 = 108
- Equivalents of Ag = x/108
For Oxygen:
- Volume of O₂ at STP = 5600 mL = 5.6 L
- Molar volume at STP = 22.4 L (using standard value)
- Moles of O₂ = 5.6/22.4 = 0.25 mol
- n-factor for O₂ = 4 (O₂ + 4e⁻ → 2O²⁻)
- Equivalents of O₂ = 0.25 × 4 = 1
Applying equivalence:
Answer: 108
Note: If using molar volume = 22.7 L (newer STP definition), the answer would be 107 g, which is also accepted.
JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Integer answer