What do you mean which of the following happened first. You have to give the example
When HCl reacts with a metal, hydrogen gas will be evolved. To test this gas, insert a burning splinter into the outlet of gas, the flame will be extinguished with a pop sound. This will confirm the gas is hydrogen.
<h3>
flammable liquids will catch on fire and burn easily at normal working temperatures. Combustible liquids have the ability to burn at temperatures that are usually above working temperatures.</h3>
<em>Hope this helped! :)</em>
Answer : The concentration after 17.0 minutes will be, 
Explanation :
The expression for first order reaction is:
![[C_t]=[C_o]e^{-kt}](https://tex.z-dn.net/?f=%5BC_t%5D%3D%5BC_o%5De%5E%7B-kt%7D)
where,
![[C_t]](https://tex.z-dn.net/?f=%5BC_t%5D)
= concentration at time 't' (final) = ?
![[C_o]](https://tex.z-dn.net/?f=%5BC_o%5D)
= concentration at time '0' (initial) = 0.100 M
k = rate constant = 
t = time = 17.0 min = 1020 s (1 min = 60 s)
Now put all the given values in the above expression, we get:
![[C_t]=(0.100)\times e^{-(5.40\times 10^{-3})\times (1020)}](https://tex.z-dn.net/?f=%5BC_t%5D%3D%280.100%29%5Ctimes%20e%5E%7B-%285.40%5Ctimes%2010%5E%7B-3%7D%29%5Ctimes%20%281020%29%7D)
![[C_t]=4.05\times 10^{-4}M](https://tex.z-dn.net/?f=%5BC_t%5D%3D4.05%5Ctimes%2010%5E%7B-4%7DM)
Thus, the concentration after 17.0 minutes will be,
