Question

The rate constant for disappearance of reactant as mentioned in is $2\times {10}^{-2}mol{L}^{-1}se{c}^{-1}$, if the concentration of the reactant after 25 sec is 0.25M, the initial concentration is:

• A. 0.75 M
• B. 0.89 M
• C. 1.03 M
• D. 1.46 M

Answer 1

The correct option is A 0.75 M

From rate constant it can be seen that it is zero order reaction and $a-x=kt;$ $a=x+kt$ $=0.25+2\times {10}^{-2}\times 25=0.75$ M.