the weight of copper ( atomic weight-63.5u) displaced Cu2 + ions by the quantity of electricity which displaces 11200 ml of H2 at STP will be
Answers
For copper
molar mass of Cu = 63.5 g
Cu ^2+ ---> Cu + 2 e -
no of electrons exchanged = n factor = 2
As per the formula ,
Weight / Equivalent weight = charge / F
We know that ,
Equivalent weight = molar mass / n factor
weight× n factor / molar mass = charge / F
Substituting the values in the above equation
W× 2 / 63.5 = Q / F ...(1)
For dihydrogen
H 2 ---> 2H ^+ + 2 e-
n factor of hydrogen = 2
volume of H 2 = 11200 ml = 11.2 L
As per the formula ,
Weight / Equivalent weight = charge / F
We know that ,
Equivalent weight = molar mass / n factor
weight× n factor / molar mass = charge / F ...(2)
we also know that ,
weight / molar mass = moles ...(3)
moles = Volume / 22.4 L ....(4)
From equation (3) and(4) we can conclude that ,
weight / molar mass =Volume / 22.4 L ...(5)
Substituting (5) in (2) we get ,
vol × n factor / 22.4 = Q / F ...(6)
As Q / F is constant equating (1 ) and (6)
W× 2 / 63.5 = Vol×2 / 22.4
W / 63.5 = 11.2 / 22.4
W = 63.5 / 2
W = 31.25 g