Which of the following is NOT true about order of a reaction?

Calculate rate constant of first order reaction if concentration of reactant decreases by $90 \%$ in 30 minute?

The reaction $2 \mathrm{~A}+\mathrm{B}+\mathrm{C} \longrightarrow \mathrm{D}+\mathrm{E}$ is found to be first order in A , second order in B and zero order in C . What is the effect of increasing concentration of all reactants twice?

Identify order of following reaction.

$$\mathrm{H}_2 \mathrm{O}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{l})}+\mathrm{O}_{2(\mathrm{~g})}$$