Question

A current of .2 is paass in aqueous solution of copper sulphate for one hour calculate the mass of copper diposit.

Answer 1

current passing through aqueous solution of copper sulphate, i = 0.2A

Time taken , t = 1 hour = 3600sec

so, charge , q = it

= 0.2 × 3600 C

= 720 C

1 mole of electron equivalent to 96500C charge.

so, no of mole of electrons = 720/96500 = 0.00746 mol

as chemical reaction is ...

Cu²+ + 2e– ⇔Cu

two moles of electrons need to deposit 1 mole of copper.

so, no of mole of copper = no of mole of electrons/2

= 0.00746/2 = 0.00373 mol

now, mass of deposited copper = mole of copper × atomic mass

= 0.00373 × 63.5

= 0.236855 ≈ 0.24g

hence, mass of deposited copper is 0.24g