Correct Answer - C
`N_(2)(g) +O_(2) (g) hArr 2NO(g)`
`K_(c) =4 xx 10^(-4)`
`2NO(g) hArr N_(2) (g) + O_(2) (g)`
`K_(c) =1/(K_(c)) =(1)/((4xx10^(-4)))= 0.25 xx 10^(4)`
`NO(g) hArr 1/2 N_(2)(g) + 1/2 O_(2) (g)`
`K_(c) =(K_(c))^(1//2) =(0.25 xx 10^(4))^(1//2)`
`=0.5 xx 10^(2) =50`