According to the Arrhenius equation,a plot of the logarithm of the rate constant $(\log \, k)$ versus which of the following yields a straight line?

The specific rate constant of a $1^{st}$ order reaction depends on the

For a reaction $E_a = 0$ and $k = 3.2 \times 10^8 \ s^{-1}$ at $300 \ K$. The value of frequency factor at $400 \ K$ would be

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 $(R=8.3 \ J \ K^{-1} \ mol^{-1})$

If $E_f$ and $E_r$ are the activation energies of forward and reverse reactions and the reaction is known to be exothermic,then

Assertion : If the activation energy of a reaction is zero,temperature will have no effect on the rate constant.
Reason : Lower the activation energy,faster is the reaction.