Correct Answer - C
For equation (i),
`NO(g)(1)/(2)O_2(g)hArr NO_2(g)`
`K_1=([NO_2])/([NO][O_2]^(1//2))` ....(i)
For reaction (ii)
`2NO_2(g)hArr2NO(g)+O_2(g)K_2=([NO]^2[O_2])/([NO_2]^2)`.....(ii)
Now, on reversing equation (i), we get,
`(1)/(k_(1))=(1)/(([NO_(2)])/([NO][O_(2)]^(1//2)))=([NO][O_2]^(1//2))/([NO_2]^2)`
`(1/(K_1))^2={([NO][O_2]^(1//2))/([NO_2])}^2=([NO]^2[O_2])/([NO_2]^2)=K_2`