Hot copper turnings can be used as oxygen getter for inert gas supplies by slowly passing the gas over the turnings at `600 K`.
`2Cu_((s))+1//2O_(2(g))hArrCu_(2)O_((s))`,
`(K_(p)=7.5xx10^(10)atm^(-1/2))`. The number of molecules per litre left after equilibrium has reached are:

Options

A. `2.17`
B. `2.17xx10^(23)`
C. `3.61xx10^(24)`
D. `1.78xx10^(22)`

Explanation

`K_(p)=(P_(O_(2)))^(-1//2)`
`:. 7.5xx10^(10)=(P_(O_(2)))^(-1//2)`
`:. P_(O_(2))=1.78xx10^(-22)`
Now, `PV=nRT`
` :. N=(1.78xx10^(-22)xx1)/(600xx0.0821)=3.61xx10^(-24)`
`:.` Number of molecules of `O_(2)` left
`=3.61xx10^(-24)xx6.023xx10^(23)=2.17`