If the pressure of ` H_2` gas is increase from (1) atm to `100` atm. Keeping `H^+` concentration constatn at ` 1` M, the veltage of hydrogen half cell at `25^@ C` will be .

Options

A. ` 0.0591 V`
B. ` 0. 59 V`
C. ` 0.0295 V`
D. ` 0.118 V`

Answer

A

Explanation

`H_2 rarr 2H^+ +2e^(-)`
`(1atm) (1 M)`
`:. E_H_2 //H^(+) = E_(H_2//H^(+))^@ - (0.591)/9 log.([H^+]^2)/(PH_2)`
` = 0.00 - (0.59 1)/2 log .((1)^2)/1 = 0.00 V`
Now , pressure is increase from atm ot ` 100` atm
`:. E_(H_2//H^+) =E_(H_2//H^+)^@ - (0.00591)/2 log.([H^+]^2)/(P_(H_2))`
` = 0- ( 0. 0 591)/2 log 10^(-2) = 0.591 V`.