Answer any seven questions of the following:
`CuSO_4` solution is electrolysed for 20 minutes with a current of 3 amperes. What mass of copper will be deposited at the cathode?

Explanation

Given, time(t) = 20 minutes = `20xx60=1200sec`
Current (i) = 3 ampers
`thereforeQ=it=3xx1200=3600C`
Also, `therefore` Eq. mass of Cu = 31.75
`therefore` Molar mass of Cu = `2xx31.75=63.5g`
`(therefore` It has (+) 2 charge)
Now,
`therefore2xx96500C` charge gives Cu = 63.5 g
`therefore3600` C charge will have `Cu=(63.5xx3600)/(2xx96500)=1.18g`
Thus, mass of copper (Cu) deposited at cathode = 1.18 g