# Decomposition of $H_2O_2$ follows a first order reaction. In fifty minutes the concentration of $H_2O_2$ decreases from $0.5$ to $0.125\; M$ in one such decomposition. When the concentration of $H_2O_2$ reaches $0.05\; M$, the rate of formation of $O_2$ will be :
( A ) $2.66 \; L\;min^{-1}$ at STP
( B ) $1.34 \times 10^{-2}\; mol\; min^{-1}$
( C ) $6.93 \times 10^{-4}\; mol\; min^{-1}$
( D ) $6.93 \times 10^{-2}\; mol\; min^{-1}$