Answer:
[tex][PH_3]=0.30M[/tex] but see detailed explanation, please.
Explanation:
Hello there!
In this case, unfortunately, we are not given the rate constant but we can set up a reaction according to the information available on the internet:
[tex]4PH_3\rightarrow P_4+6H_2[/tex]
Whose rate constant is 0.0375/s. In such a way, it is possible infer that this is first-order reaction whose integrated rate law is:
[tex][PH_3]=[PH_3]_0exp(-kt)[/tex]
Thus, given the initial concentration, rate constant and elapsed time, the final concentration of PH3 would be:
[tex][PH_3]=(0.95M)exp(-30.50s*0.0375/s)\\\\[/tex]
[tex][PH_3]=0.30M[/tex]
However, it is important to keep in mind this result may vary according to your actual question.
Regards!