What is the average rate of reaction when change in concentration of product is 0.05 M in 20 seconds?

Identify role of glycerol in following reaction.

$$ 2 \mathrm{H}_2 \mathrm{O}_{2(\ell)} \xrightarrow{\text { glycerol }} 2 \mathrm{H}_2 \mathrm{O}_{(\ell)}+\mathrm{O}_{2(g)} $$

The slope of a graph $\log [A]_1$ versus ' $t$ ' for first order reaction is $-2.5 \times 10^{-3} \mathrm{~s}^{-1}$. Find rate constant of the reaction?

Identify the order of following reaction?

$$ 2 \mathrm{NO}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} $$