Question
The electrochemical equivalent of a metal is $${3.35109^{ - 7}}kg$$ per Coulomb. The mass of the metal liberated at the cathode when a $$3A$$ current is passed for 2 seconds will be
A.
$$6.6 \times {10^{57}}kg$$
B.
$$9.9 \times {10^{ - 7}}kg$$
C.
$$19.8 \times {10^{ - 7}}kg$$
D.
$$1.1 \times {10^{ - 7}}kg$$
Answer :
$$19.8 \times {10^{ - 7}}kg$$
Solution :
The mass liberated $$m,$$ electrochemical equivalent of a metal $$Z,$$ are related as
$$\eqalign{
& m = Zit \cr
& \Rightarrow m = 3.3 \times {10^{ - 7}} \times 3 \times 2 = 19.8 \times {10^{ - 7}}kg \cr} $$