# The rates in order of fastest to slowest for this reaction: a 5g of powdered $Mg(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2(g)$ are:

 S.No Temperature $(^oC)$ Concentration of HCl 1 60 5 2 40 5 3 60 10

$\begin{array}{1 1}(a)\;2,1,3&(b)\;3,1,2\\(c)\;1,2,3&(d)\;2,3,1\end{array}$

If temperature is higher and concentration of reactant is higher then rate would be higher.So (b) is correct answer.