Kolbe discovered the method of preparation of hydrocarbon in which sodium salt of carboxylic acid is electrolysed.If aqueous solution of CH_(3)COONa is electrolysed by a current of 19.3A passed for T second and total volume of gas collected at anode and cathode is 268.8mL at S.T.P then value of T is
Answers
Concept:
The amount of material oxidised or reduced at each electrode during electrolysis is exactly proportional to the amount of electricity passed through the cell. It equals the Product of current and time.
Given:
Current passes = 19.3 A
Volume collected at anode and cathode = 268.8ml at STP
Find:
Value of Time t
Solution:
According to Faraday first law of electrolysis
m ∝ it
m = zit
where m is mass, i is current and t is time.
as z = equivalent weight / 1 F
z = equivalent weight / 96500
so our formula will become
m = equivalent weight × i × t / 96500
and as equivalent weight = molecular weight /nf
where nf denotes the n factor
so our formula will become
m = ( (molecular weight × i × t) / (96500 × nf) )
m/molecular weight = ( (i × t) / (96500 × nf) )
mole = ( (i × t) / (96500 × nf) )
We can find out the number of moles by ideal gas equation
PV = nRT
at STP, P = 1 atm and T = 273 K
volume given to us is 268.8 ml which is also 0.2688 L
So,
0.2688 = n × 0.0821 × 273
0.0119 = n
So number of mole is 0.0119
Putting it and all other values into faraday formula
mole = ( (i × t) / (96500 × nf) )
0.0119 = 19.3 × t / 96500
as nf is one for CH3COONa
t = 59.5 seconds
Value of time came out to be 59.5 seconds
Hence, The value of time for which current is passed is 59.5 seconds
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Answer:
here is the answer hope.. it helps
