Critical temperature for carbon dioxide and methane are 3 1.1°c and - 81.9°C respectively. Which of these has stronger intermolecular forces?

Critical temperature is the temperature above which the gas cannot be liquefied. Higher the critical temperature, more easily the gas can be liquefied, i.e. stronger are the intermolecular forces. Hence, ${\mathrm{CO}}_2$ has stronger intermolecular forces than ${\mathrm{CH}}_4$.