Consider an endothermic reaction $X \to Y$ with the activation energies $E_b$ and $E_f$ for the backward and forward reactions,respectively. In general:

$A$ reaction with low activation energy is always...............

The activation energy of a reaction is $0$. The rate constant of the reaction:

Which of the following statements is correct for the activation energy of a reaction?

The graph obtained between $\ln k$ ($k=$ Rate constant) on $y$-axis and $1/T$ on $x$-axis is a straight line. The slope of it is $-4 \times 10^4 \ K$. The activation energy of the reaction (in $kJ \ mol^{-1}$) is $(R=8.3 \ J \ K^{-1} \ mol^{-1})$

Who discovered collision theory? On which the collision theory is based?