Question

What is the volume of Hydrogen liberated at N.T.P by the charge which liberates $ 0.3175gm $ of copper?
A. $ 224cc $
B. $ 112cc $
C. $ 56cc $
D. None of these

Answer 1

Hint :To solve this question, first we will briefly define the N.T.P system of liberation of element. And then we will first liberate the given quantity of copper to get the charge. As we already know that, ( $ 31.75gm $ of copper is liberated by $ 96500C $ of charge ).

Complete Step By Step Answer:
Normal Temperature and Pressure NTP is commonly used as a standard condition for testing and documentation of fan capacities: NTP - Normal Temperature and Pressure - is defined as air at $ 200C $ ( $ 293.15K,680F $ ) and $ 1atm $ .
As we know that, $ 31.75gm $ of copper is liberated by $ 96500C $ of charge.
 $ \because 1gm $ of copper is liberated by $ \dfrac{{96500}}{{31.75}}C $ of charge.
 $ \therefore 0.3175gm $ of copper will be liberated by $ \dfrac{{96500 \times 0.3175}}{{31.75}}C $ or $ 965C $ of charge.
Now, as we know that, $ 96500C $ of charge liberates $ 11.2litre $ of hydrogen,
 $ 965C $ of charge will liberate: $ \dfrac{{11.2 \times 1000 \times 965}}{{96500}} = 112cc $ $ $ .
Hence, the correct option is (B.) $ 112cc $ .

Note :
So, Copper does not liberate hydrogen from the solution of dilute hydrochloric acid because copper lies below the hydrogen in the electrochemical series.