Question

How many atoms of calcium will be deposited from a solution
of CaCl₂ by a current of 25 mA flowing for 60 seconds?
(a) 4.68 × 10¹⁸ (b) 4.68 × 10¹⁵
(c) 4.68 × 10¹² (d) 4.68 × 10⁹

Answer 1

Answer:

Explanation:

We know that :

M=Z\times I\times tM=Z×I×t                      

 But, Z=\dfrac { Equivalent\quad weight }{ 96500 }Z=  

96500

Equivalentweight

​  

 

Put the value of Z in above equation, we get :

M=\dfrac { 20 }{ 2\times 96500 } \times 25\times { 10 }^{ -3 }\times 60M=  

2×96500

20

​  

×25×10  

−3

×60

M=0.00015544M=0.00015544

No. of moles =\dfrac { 0.00015544 }{ 20 } =0.000007772=  

20

0.00015544

​  

=0.000007772

No. of atoms =0.000046811\times { 10 }^{ 23 }=4.6811\times { 10 }^{ 18 }=0.000046811×10  

23

=4.6811×10  

18

 

Hence the correct option is A.