Question

If an aqueous solution of HNO3 is electrolyzed for 13.00 min at a steady current of 1.45 A, what volume of H2 (g) at 25.0oC and 1.03 atm will be collected at the cathode? vol H2 (L)

Answer 1

Answer: 0.14 Liters

Step-by-step explanation:

`Q=I* t`

where Q= quantity of electricity in coloumbs

I = current in amperes = 1.45 A

t= time in seconds = 13 min=
`13* 60 =780s`

`Q=1.45A* 780s=1131C`

`HNO_3\rightarrow H^++NO_3^-`

`2H^++2e^-\rightarrow H_2`

`96500* 2=193000Coloumb` of electricity deposits 1 mole of
`H_2`

1131 C of electricity deposits =
`(1)/(193000)* 1131=5.86* 10^(-3)moles` of
`H_2`

According to the ideal gas equation:'

`PV=nRT`

P = Pressure of the gas = 1.03 atm

V= Volume of the gas = ?

T= Temperature of the gas = 25°C = 298 K (0°C = 273 K)

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas=
`5.86* 10^(-3)moles`

`V=(nRT)/(P)=(5.86* 10^(-3)* 0.0821* 298)/(1.03)=0.14L`

Thus the volume of hydrogen gas at
`25^0C` and 1.03 atm will be 0.14 Liters.