Which of the following gases will have the same rate of diffusion under identical conditions?

(i) CO  

$\mathrm{ii}) {\mathrm{CO}}_2$

$\mathrm{iii}) {\mathrm{N}}_2\mathrm{O}$

$\mathrm{iv}) {\mathrm{N}}_2$

$\mathrm{V}) {\mathrm{C}}_2{\mathrm{H}}_4$

$\mathrm{Vi}){\mathrm{C}}_3{\mathrm{H}}_8$

A) Molar mass of CO = 28 

Molar mass of ${\mathrm{CO}}_2$ = 44

Molar mass of ${\mathrm{C}}_2{\mathrm{H}}_4=28$

B) Molar mass of ${\mathrm{CO}}_2=44$

Molar mass of ${\mathrm{C}}_2{\mathrm{H}}_4=28$

Molar mass of ${\mathrm{N}}_2\mathrm{O}=44$

C) Molar mass of ${\mathrm{C}}_3{\mathrm{H}}_8=44$

Molar mass of ${\mathrm{N}}_2\mathrm{O}=44$

Molar mass of ${\mathrm{CO}}_2=44$

D) Molar mass of CO = 28

Molar mass of ${\mathrm{N}}_2=28$

Molar mass of ${\mathrm{C}}_2{\mathrm{H}}_4=28$

Molar mass of ${\mathrm{C}}_2{\mathrm{H}}_4=44$

Hence , same rate of diffusion means same molecular weight. i.e ${\mathrm{C}}_3{\mathrm{H}}_8,{\mathrm{N}}_2\mathrm{O},{\mathrm{CO}}_2$ have same rate of diffusion.