Hydrogen Peroxide Decomposes into Water and Oxygen in a First-Order $\ell$

Multiple Choice

Hydrogen peroxide decomposes into water and oxygen in a first-order process. H₂O₂(aq) ? H₂O( $\ell$ ) + 1/2 O₂(g)
At 20.0 °C, the half-life for the reaction is 3.92 × 10⁴ seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?

A) 1.2 × 10^-5 M
B) 0.034 M
C) 0.074 M
D) 0.22 M
E) 0.52 M