A vessel at `1000 K` contains carbon dioxide with a pressure of `0.5 atm`. Some of the carbon dioxide is converted to carbon monoxide on addition of graphite. Calculate the value of `K_(p)` if total pressure at equilibrium is `0.8 atm`.

Answer

1.8 atm

Explanation

The reaction is `CO_2(g) + C(s) hArr 2CO(g)`
Let the decrease in pressure of `CO_2` due to reaction be p atm.
Increase in pressure due to formation of CO=2p atm
Pressure of `CO_2` left =(0.5-p) atm
Pressure of CO=2p atm.
Total pressure =0.5 - p + 2p =(0.5+p) atm
`therefore ` 0.5+p = 0.8 or p=0.3
`therefore` At equilibrium , `p_(CO_2)` =0.5-0.3=0.2 atm
`2p_(CO)`=0.3 x 2 = 0.6 atm
`K=(p_"CO")^2/p_(CO_2)=(0.6)^2/0.2`=1.8atm