Why does physical adsorption decrease with an increase in temperature?

Froth floatation process for the concentration of sulphide ores is an illustration of the practical application of

Which of the following is not a characteristic of physical adsorption?

Which of the following is not a characteristic of chemisorption?

For the adsorption of hydrogen on platinum,the activation energy is $30 \ kJ \ mol^{-1}$ and for the adsorption of hydrogen on nickel,the activation energy is $41.4 \ kJ \ mol^{-1}$. The logarithm of the ratio of the rates of chemisorption on equal areas of the metals at $300 \ K$ is $........$ (Nearest integer). Given: $\ln 10 = 2.3$,$R = 8.3 \ J \ K^{-1} \ mol^{-1}$.

Which of the following is incorrect for physisorption?