Question

For the reaction PCl5​→PCl3​+Cl2​, the rate and rate constant are 1.02×10−4mol L−1s−1 and 3.4×10−5s−1, respectively, at a given instant. The molar concentration of PCl5​ at that instant is:

• A. 8.0mol/L
• B. 3.0mol/L
• C. 0.2mol/L
• D. 2.0mol/L

Hint:

The concentration of PCl5​ can be determined using the rate law Rate=k[PCl5​].

Answer 1

The Correct Option is B

Using the rate law for a first-order reaction: Rate=k[$PCl_5​$], the concentration is calculated as [$PCl_5​$​]=kRate​=3.4×10−51.02×10−4​=3.0mol/L.