Choose the appropriate word(s) from the bracket [lead poisoning, zero, phosgene, dependent, cancer…

Choose the appropriate word(s) from the bracket [lead poisoning, zero, phosgene, dependent, cancer, independent, diethyl ether, first, ethyl carbonate, ethene]: For a particular reaction, the value of rate constant is $0\cdot05\text{ sec}^{-1}$. The reaction is of ____ order and will be ____ of the initial concentration.