Question

The negative Zn plate of a Daniel cell, sending a constant current through a circuit, decreases in mass by 0.13 gm in 30 minutes. If the chemical equivalent of Zn and Cu are 32.5 and 31.5 respectively, the increase in mass of the copper plate is:

• A. 0.141 gm
• B. 0.126 gm
• C. 0.242 gm
• D. 0.180 gm

Answer 1

Answer: (B)

0.126 gm

The relationship between mass and electrochemical equivalent is $\frac{m_1}{m_2}=\frac{E_1}{E_2}$.

Substitute values in the above expression,

$M_{Cu}=\frac{31.5}{32.5}\times \left(.13\right)=0.126gm$