Question

The weight of silver displaced by a quantity of electricity which displaces 5600 ml of O₂ at STP will be

• A. 5.4 g
• B. 108.0 g
• C. 54.0 g
• D. 10.8 g

Answer 1

The correct option is B

108.0 g

Explanation for correct option:

(B) 108.0 g

Step 1: Specifying the given credentials and assumptions:

• Amount of Oxygen($O_2$) displaced at STP = 5600 ml
• Volume occupied by 1 mole of $O_2$ at STP = 22400 ml
• Molecular weight of Silver($Ag$) = 108 g

Step 2: Computing the moles of Oxygen:

• Number of Oxygen($O_2$) displaced, $n_{O_2}=\frac{5600ml}{24400ml}=0.25$

Step 3: Using Faraday's Second Law:

• Faraday's Second Law states that the mass of the substances deposited is directly proportional to their equivalent weight when the same amount of electricity is passed through the electrolytes.
• 4 moles of electrons are produced by 1 mole of $O_2$ and 1 mole of electrons is produced by 1 mole of Silver( $Ag$).

$$\begin{gathered} \frac{W_{Ag}}{M_{Ag}}=\frac{W_{O_2}}{M_{O2}} \\ \Rightarrow \frac{W_{Ag}}{M_{Ag}}\times 1=\frac{W_{O_2}}{M_{O2}}\times 4 \\ \Rightarrow \frac{W_{Ag}}{108}\times 1=0.25\times 4 \\ \Rightarrow W_{Ag}=108g \end{gathered}$$

Explanation for incorrect options:

Since, the correct weight of silver is 108.0 g. Hence, options (A), (C), and (D) are incorrect.

Hence, option(B) is the correct option that the weight of silver displaced by electricity is 108 g.